(;%0;538#)#(;%0;838#;PP# 7DSH#'ULYHV IRU#VWDQGDUG#DQG#H;WHQGHG0/HQJWK#FRQILJXUDWLRQV 6&6,# 5HIHUHQFH 510503-004
Copyright Copyright 1994 by Exabyte Corporation. All rights reserved. This item and the information contained herein are the property of Exabyte Corporation.
Product Warranty Caution The EXB-8505, EXB-8505XL, EXB-8205, and EXB-8205XL 8mm Cartridge Tape Subsystems (CTSs) are warranted to be free from defects in materials, parts, and workmanship and will conform to the current product specification upon delivery. For the specific details of your warranty, refer to your sales contract or contact the company from which the CTS was purchased.
Changes and Enhancements to This Manual This revision (510503-004) of the EXB-8205 and EXB-8505 SCSI Reference for Standard and eXtended-Length (XL) Configurations replaces the EXB-8205 User’s Manual (510501-001) and the EXB-8505 User’s Manual (510503-002). This manual includes the following changes and enhancements: The title of this manual has been changed from “User’s Manual” to “SCSI Reference” to more accurately reflect its content.
Contents About This Manual xix 1 CTS Features 1-1 1.1 Comparison of the Data Formats Supported by the CTSs 1.2 Structure of Data on Tape . . . . . . . . . . . . . . . . . . . Physical Track Structure . . . . . . . . . . . . . . . . . . Data Elements on Tape . . . . . . . . . . . . . . . . . . . 1.3 Controls and Indicators . . . . . . . . . . . . . . . . . . . . Unload Button . . . . . . . . . . . . . . . . . . . . . . . . LEDs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.
3 Implementing CTS Operations 3-1 3.1 Using Data Cartridges . . . . . . . . . . . . . . . . . . . . . Loading Data Cartridges . . . . . . . . . . . . . . . . . . Unloading Data Cartridges . . . . . . . . . . . . . . . . 3.2 Controlling the Format of Data on the Tape . . . . . . . . 3.3 Using Data Compression . . . . . . . . . . . . . . . . . . . Using the EXB-8505 to Write Compressed Data . . . . . Using the EXB-8205 to Write Compressed Data . . . . . 3.4 Setting the Size of Data Blocks . . . . . . . . .
6 LOAD/UNLOAD (1Bh) 6-1 6.1 About This Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-2 6.2 Field Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6-4 7 LOCATE (2Bh) 7-1 7.1 About This Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-2 7.2 Field Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7-4 7.3 Exceptions and Error Conditions . . . . . . . . . . . . . . . . . . .
11 PREVENT/ALLOW MEDIUM REMOVAL (1Eh) 11-1 11.1 About This Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-2 11.2 Field Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11-3 12 READ (08h) 12-1 12.1 About This Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 12.2 Field Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12-2 12.3 Exceptions and Error Conditions . . . . . . . . . . .
18 REQUEST SENSE (03h) 18-1 18.1 About This Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2 18.2 Field Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-2 18.3 Extended Sense Bytes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18-3 19 RESERVE UNIT (16h) 19-1 19.1 About This Command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 19-2 19.2 Field Definitions . . . . . . . . . . . . . . . . . . . . .
25 WRITE (0Ah) 25.1 25.2 25.3 25.4 25.5 25-1 About This Command . . . . . . Field Definitions . . . . . . . . . . Tape Positioning . . . . . . . . . . Data Buffering . . . . . . . . . . . Exceptions and Error Conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Appendix D SCSI Bus Message Processing and Error Recovery D-1 SCSI Bus Error Recovery (Initiators Supporting the Command Complete Message Only) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-2 Message Processing/SCSI Bus Error Recovery (Initiators Supporting Other Messages) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . D-3 Appendix E Error Information E-1 REQUEST SENSE Information . . . . . . . . Sense Key = 0h (No Sense) . . . . . . .
Figures CTS Features Figure 1-1 EXB-8505 (top) and EXB-8205 (bottom) . . . . . . . . . . . . . Figure 1-2 Relationship of 8mm physical track structures to logical data formats . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure 1-3 Structure of data on tape (8500/8500c physical format) . . . Figure 1-4 Front panel of the EXB-8505 . . . . . . . . . . . . . . . . . . . Figure 1-5 LEDs on the EXB-8505’s front panel . . . . . . . . . . . . . . . . . . . . . . 1-2 . . . . . . . . . . . . . . . .
Figure D-10 Message processing during the Data In phase of commands other than READ . . . . . . . . . . . . . . . . . . . . . . . . . Figure D-11 Message processing during the Status In phase . . . . . . . . . Figure D-12 Message processing during Command Complete Message In phase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Figure D-13 Message processing after CTS reselects initiator with Identify message . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Tables CTS Features Table 1-1 Comparison of CTS features . . . . . . . . . . . . . . . . . . . . Table 1-2 Read and write compatibility of Exabyte 8mm Cartridge Tape Subsystems and data formats . . . . . . . . . . . . . . . . . Table 1-3 Data format features . . . . . . . . . . . . . . . . . . . . . . . . . Table 1-4 CTS states indicated by the LEDs . . . . . . . . . . . . . . . . . . . . . . . . 1-3 . . . . . . 1-4 . . . . . . 1-5 . . . . . 1-16 SCSI Communication . . . . . . . . . . . . . . . . . .
LOG SELECT (4Ch) Table 8-1 Valid combinations of values for the fields in the LOG SELECT CDB . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Table 8-2 Parameter Codes for LOG SELECT command . . . . . . . . . . . Table 8-3 Parameter Lengths for LOG SELECT command . . . . . . . . . . Table 8-4 REQUEST SENSE data for LOG SELECT errors and exceptions . . . . . . . . . . . . . . . . . . . . .
SPACE (11h) Table 22-1 Values of Code field for the SPACE command . . . . . . . . . . . . . . 22-3 WRITE (0Ah) Table 25-1 Legal locations for appending data on a previously written tape . . . . 25-4 Table 25-2 Action if LEOT or LEOP is encountered during a WRITE command . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25-7 WRITE FILEMARKS (10h) Table 27-1 Legal positions for appending filemarks and setmarks . . . . . . . . .
SCSI Bus Message Processing and Error Recovery Table D-1 Responses to the Attention signal . . . . . . . . . . . . . . . . . . . . . . . D-3 Error Information Table E-1 REQUEST SENSE information for Sense Key 0h . Table E-2 REQUEST SENSE information for Sense Key 1h . Table E-3 REQUEST SENSE information for Sense Key 2h . Table E-4 REQUEST SENSE information for Sense Key 3h . Table E-5 REQUEST SENSE information for Sense Key 4h . Table E-6 REQUEST SENSE information for Sense Key 5h .
xviii EXB-8205 and EXB-8505 (Standard and XL) 510503
About This Manual This manual provides reference information for developing software to support applications for the EXABYTE® EXB-8505 or EXB-8205 8mm Cartridge Tape Subsystem (CTS). It also includes information about the “eXtended-Length” (XL) configurations of these CTSs (EXB-8505XL and EXB-8205XL). Contents of This Manual This manual contains the following information: Chapter 1 briefly describes the important features of the CTSs.
Appendix E lists the possible combinations of values for the Additional Sense Code (ASC) and Additional Sense Code Qualifier (ASCQ) fields returned by the REQUEST SENSE (03h) command. It also lists the Fault Symptom Codes that may be returned by the REQUEST SENSE command and recommends recovery procedures for each Fault Symptom Code. A glossary and index are included at the back of this manual.
Related Publications The following publications provide additional, related information.
Notes: xxii EXB-8205 and EXB-8505 (Standard and XL) 510503
1 CTS Features This chapter is an overview of the features of the EXABYTE® EXB-8505 and EXB-8205 8mm Cartridge Tape Subsystems (CTSs).
1 CTS Features Shown in Figure 1-1, the EXB-8505 and EXB-8205 are enhanced 8mm digital helical-scan cartridge tape subsystems (CTSs) packaged in the industry-standard 5.25-inch half-high form factor. These CTSs include a Small Computer System Interface (SCSI) controller and are available in single-ended and differential SCSI configurations.
1 CTS Features You can distinguish an XL CTS from a non-XL CTS by checking the unload button. The XL CTSs have a raised diamond pattern on the unload button. The non-XL CTSs have a smooth unload button with an oval-shaped indentation. Note: Unless otherwise noted, the terms “EXB-8505” and “EXB-8205” include the XL configurations of these CTSs. Table 1-1 is a comparison of the features of the CTSs. Table 1-1 Comparison of CTS features EXB-8505 Form factor Data formats supported EXB-8205 Half-high 5.
1 CTS Features 1.1 Comparison of the Data Formats Supported by the CTSs The EXB-8505 reads and writes data in four logical formats: 8200 8200c (compressed) 8500 8500c (compressed) The EXB-8205 reads and writes data in two logical formats: 8200 8200c (compressed) Table 1-2 shows the read and write compatibility of the four logical data formats with other Exabyte 8mm Cartridge Tape Subsystems. Table 1-3 compares the data format features of the EXB-8505 and EXB-8205.
1 CTS Features Table 1-3 Data format features 8200 format (EXB-8205 and EXB-8505) 8200c format* (EXB-8205 and EXB-8505) 8500 format (EXB-8505) 8500c format* (EXB-8505) Maximum sustained data transfer rate 262 KBytes/sec 500 KBytes/sec 1.0 MByte/sec Maximum capacity on 112m tape 2.5 GBytes 5.0 GBytes 10.0 GBytes Maximum capacity on 160m XL tape (XL CTSs only) 3.5 GBytes 7.0 GBytes 14.0 GBytes Track structure Helical scan: One write head writes a single data track with a –10° azimuth.
1 CTS Features 1.2 Structure of Data on Tape This section provides more in-depth information about the data formats supported by the CTSs. It discusses: The physical structure of tracks written to tape—how data tracks are placed on the tape and how the physical track structure corresponds to the logical data formats supported by the CTSs.
1 CTS Features Single-Azimuth Compressed (8200c Physical Format) Both the EXB-8505 and EXB-8205 write and read this format. In this format: One write head writes a single track for each revolution of the drum. Three servo areas are written in each track (at the beginning, middle, and end) to increase tracking accuracy. Each track contains search fields for high-speed search. By default, data is compressed.
1 CTS Features Figure 1-2 Relationship of 8mm physical track structures to logical data formats 1-8 EXB-8205 and EXB-8505 (Standard and XL) 510503
1 CTS Features Data Elements on Tape Figure 1-3 summarizes the structure of data written to tape and shows the elements that make up data tracks and blocks. This illustration shows data written in 8500/8500c physical format. Explanations of the data elements follow the figure.
1 CTS Features Physical Beginning of Tape (PBOT) PBOT is located at the point on the tape where the translucent leader material is attached to the media. This position is detected by an optical sensor in the tape transport mechanism. Note: The leader material of the EXATAPE 160m XL data cartridge contains a Recognition System stripe that identifies it as data-grade media.
1 CTS Features The CTS writes an EOD mark when you press the unload button or issue one of the following commands immediately after the CTS completes a WRITE or WRITE FILEMARKS operation: ERASE (19h) LOAD/UNLOAD (1Bh) LOCATE (2Bh) in the reverse direction REWIND (01h) SPACE (11h) in either direction The EOD mark is overwritten when additional data is appended to the last data on the tape.
1 CTS Features Physical Blocks Each physical track contains eight physical blocks. A physical block containing user data includes the following: 14 bytes of header information Up to 1,024 bytes of user data 2 bytes of cyclic redundancy check (CRC) data 400 bytes of error correction code (ECC) data Note that the header, ECC data, and CRC data do not affect the user data capacity of the tape.
1 CTS Features Search Fields Each track of data contains search fields used for high-speed search. High-speed search occurs when the initiator issues a LOCATE (2Bh) or SPACE (11h) command. The search fields are the only areas of the tape that are read during a high-speed search. They consist of small data areas interspersed with clock sync areas. The search field data contains information for locating files and blocks and detecting the end-of-data (EOD) mark during high-speed searches.
1 CTS Features Figure 1-4 Front panel of the EXB-8505 Unload Button The unload button is the only operator control on the CTS. It is used to unload the tape from the CTS.
1 CTS Features LEDs The CTS uses three LEDs (see Figure 1-5) to indicate its various operating states. The LEDs indicate the following general conditions: When the top (amber) LED is on or flashing, the CTS has an error or needs to be cleaned. When the middle LED is on or flashing, SCSI bus activity is occurring. The middle LED can be green or amber, as follows: Amber When this LED is amber, the tape loaded in the CTS is in one of the compression formats (8200c or 8500c).
1 CTS Features Table 1-4 shows specific combinations of LEDs that may occur during operation.
1 CTS Features 1.4 Customizing CTS Operation with EEPROM Options When the EXB-8505 and EXB-8205 are manufactured, a number of default values are programmed into the CTS’s electronically erasable programmable read-only memory (EEPROM). These default values, called EEPROM options, include such items as power-on defaults for SCSI commands, hardware operation options, and SCSI configuration options.
1 CTS Features Notes: 1-18 EXB-8205 and EXB-8505 (Standard and XL) 510503
2 SCSI Communication This chapter provides an overview of how the Small Computer System Interface (SCSI) is implemented for the EXB-8505 and EXB-8205. It discusses the following topics: SCSI commands supported by the CTS Required format of SCSI commands Command statuses supported by the CTS SCSI bus messages supported by the CTS Note: May 1994 The ANSI Small Computer System Interface-2 (SCSI-2) Specification provides detailed information about SCSI physical characteristics.
2 SCSI Communication 2.1 Overview of SCSI Communication Table 2-1 shows the commands, status information, and messages that are supported by the CTS during SCSI bus phases. Table 2-1 Overview of SCSI communication SCSI Bus Phase Explanation Bus Free Arbitration BSY and SEL are false. The SCSI bus is idle and available for arbitration. BSY and SCSI ID assertion (highest ID wins). Selection Winning ID asserts SEL. The initiator releases I/O and BSY. The CTS sets BSY.
2 SCSI Communication SCSI Bus Phase Explanation Data In/Out Status The CTS drives the bus to one of the Data phases and sends or receives data.
2 SCSI Communication 2.2 SCSI Commands Supported by the CTSs The EXB-8505 and EXB-8205 support the SCSI commands shown in Table 2-2. Table 2-2 Supported SCSI commands Command ERASE INQUIRY LOAD/ UNLOAD LOCATE LOG SELECT LOG SENSE 2-4 Operation code (hex) 19h 12h 1Bh 2Bh 4Ch 4Dh What the CTS does in response to this command Described in Erases the tape starting from the current legal position to the physical end of tape (PEOT). Rewinds the tape when finished.
2 SCSI Communication Command Operation code (hex) MODE SELECT 15h MODE SENSE 1Ah PREVENT/ALLOW MEDIUM REMOVAL 1Eh READ 08h READ BLOCK LIMITS READ BUFFER 05h 3Ch READ POSITION 34h RECEIVE DIAGNOSTIC RESULTS 1Ch What the CTS does in response to this command Changes the CTS’s internal medium, logical unit, or device parameters to values specified by the initiator. Provides the initiator with information about the CTS’s internal medium, logical unit, and device parameters.
2 SCSI Communication Command SEND DIAGNOSTIC SPACE 2-6 Operation code (hex) 1Dh 11h What the CTS does in response to this command Performs diagnostic functions specified by the initiator. (For the initiator to receive the results of the tests, this command must be followed by a RECEIVE DIAGNOSTIC RESULTS command.) Searches forward or backward on the tape a specified number of logical blocks, filemarks, or setmarks (8500c format only).
2 SCSI Communication 2.3 SCSI Command Format The SCSI command formats for the six- and ten-byte commands are shown in the ANSI Small Computer System Interface 2 (SCSI-2) standard. The commands for the CTS are implemented according to this standard. The following are the formats for the six- and ten-byte command descriptor blocks, followed by the format of the Operation Code and the typical format for the Control byte.
2 SCSI Communication Format of the Operation Code Bit Byte 7 00 6 5 4 3 Group Code 2 1 0 1 0 Flag Link Command Code Typical Format of the Control Byte Bit Byte nn 7 6 Vendor Unique 5 4 3 Reserved 2 Note: The word Reserved or RSVD as used in field definitions for SCSI commands has one of the following meanings: Fields defined as reserved by the ANSI Small Computer System Interface 2 (SCSI-2) standard. These fields are checked for a value of 0.
2 SCSI Communication 2.4 Field Definitions for the Command Descriptor Block The following sections provide field definitions for the six- and ten-byte command descriptor blocks (CDB). Field Definitions for Six-Byte CDBs The following are the definitions of the fields shown for the six-byte CDB.
2 SCSI Communication Byte 05 - Control Byte The Vendor Unique portion of the Control byte is defined for each specific command, if used. The CTS does not support linked commands or recognize the Flag bit. The following are the field definitions for the Control byte: Bits 7 and 6 - Vendor Unique Command unique. Bits 5 through 2 - Reserved These bits are reserved. Bit 1 - Flag Not used, must be 0. Bit 0 - Link Not used, must be 0.
2 SCSI Communication Byte 06 - Reserved This byte is reserved. Bytes 07 and 08 - Transfer, Parameter List, or Allocation Length These bytes contain the transfer length, the parameter list length, or the allocation length as required by the specific command. Byte 09 - Control Byte The Vendor Unique portion of the Control byte is defined for each specific command, if used. The CTS does not support linked commands or recognize the Flag bit.
2 SCSI Communication Depending on the specific error, the Additional Sense Code (ASC) is set to Illegal Operation Code (20h), Logical Unit Not Supported (25h), or Invalid Field in CDB (24h). The Additional Sense Code Qualifier (ASCQ) is set to 0. 2.6 Command Status One status byte is sent from the CTS to the initiator at the completion of a command. The format of the status byte is shown below.
2 SCSI Communication The following are definitions of the status bytes supported by the CTS. Good Status Good status indicates that the operation specified by the CDB completed normally. For those commands that support the immediate return of status, Good status indicates that the CTS has accepted the command and will attempt to perform the operation specified by the CDB.
2 SCSI Communication Busy Busy status indicates that the CTS is in the busy state. The CTS is in a busy state when it is performing an internal operation that will not allow another command to be accepted until the operation is complete. The CTS returns Busy status for a command request until the busy state is released. For this reason, the initiator must reissue the command to the CTS. Once the busy state is released, selection operation and commands can be executed normally.
2 SCSI Communication 2.7 Message System The message system allows communication between the initiator and the CTS for physical path management. Table 2-4 lists the messages supported by the CTS. Refer to Appendix D for information about the specific actions the CTS takes in response to messages from the initiator.
2 SCSI Communication Command Complete (00h) The CTS sends the Command Complete message to the initiator to indicate that the execution of a command has terminated and that valid status has been sent to the initiator. After successfully sending this message, the CTS goes to the Bus Free phase. Extended Message (01h) The CTS supports only one Extended message, the Synchronous Data Transfer Request message.
2 SCSI Communication The format of the Synchronous Data Transfer Request message is as follows: Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 0 0 0 0 1 01 Extended Message Length 02 Extended Message Code 03 Transfer Period 04 REQ/ACK Offset Byte 00 - Extended Message The valid value for the Extended Message field is 01h, indicating that this is an extended message that contains multiple bytes.
2 SCSI Communication Save Data Pointer (02h) The CTS sends the Save Data Pointer message to direct the initiator to save a copy of its present active data pointer for the CTS. Restore Pointers (03h) The CTS sends the Restore Pointers message to direct the initiator to restore the most recently saved data pointers for the currently attached LUN to the active state. Pointers to the Command, Data, and Status locations for the LUN are restored to the active pointers.
2 SCSI Communication Initiator Detected Error (05h) The initiator sends the Initiator Detected Error message to inform the CTS that an error has occurred that does not preclude the CTS from retrying the operation. Generally, the initiator sends this message when it has detected a parity error in a non-message phase, such as Status In or Data In. The present pointer integrity is not ensured. Abort (06h) The initiator sends the Abort message to the CTS to clear the present operation.
2 SCSI Communication No Operation (08h) The initiator sends the No Operation message in response to the CTS’s request for a message when the initiator does not currently have any other valid message to send. Message Parity Error (09h) The initiator sends the Message Parity Error message to the CTS to indicate that the last message it received had a parity error. The CTS responds by re-sending the previous message.
2 SCSI Communication Identify (80h or C0h) Either the initiator or the CTS can send the Identify message. The message is used to establish the physical path connection between an initiator and the CTS. When the CTS sends the Identify message to the initiator during reconnection, an implied Restore Pointers message must be implemented by the initiator before completion of this message.
2 SCSI Communication Message Sequence When the CTS connects to the SCSI bus, the following sequence of events occurs: 1. The initiator indicates its ability to accommodate more than the Command Complete message by asserting the Attention signal in the Selection phase before the Select signal is driven true and the Busy signal is driven false. 2.
3 Implementing CTS Operations This chapter explains how to implement common CTS operations. It includes information about the following: Using data cartridges Controlling the format of data on the tape Using data compression Setting the size of data blocks Using filemarks and setmarks Using streaming vs.
3 Implementing CTS Operations 3.1 Using Data Cartridges To ensure optimum data reliability and minimize wear on the CTS’s recording heads, Exabyte strongly recommends the use of EXATAPE 8mm Data Cartridges in all Exabyte 8mm CTSs. EXATAPE 8mm Data Cartridges are available in the following lengths: 15m, 54m, 112m, 160m XL (for the EXB-8505XL and EXB-8205XL only). Important EXATAPE 160m XL 8mm Data Cartridges are intended for use in the EXB-8505XL and EXB-8205XL only.
3 Implementing CTS Operations Table 3-1 Compatibility of EXATAPE 8mm Data Cartridges and Exabyte 8mm CTSs EXATAPE 8mm Data Cartridge 15m 54m 112m 160m XL EXB-8205 and EXB-8505 ✔ ✔ ✔ Not supported (automatically ejected) EXB-8205XL and EXB-8505XL ✔ ✔ ✔ ✔ EXB-8200 and EXB-8200SX ✔ ✔ ✔ Not supported EXB-8500 and EXB-8500c ✔ ✔ ✔ Not supported Loading Data Cartridges When a data cartridge is inserted into the CTS, the tape is automatically loaded into the tape path and positioned at LBOT
3 Implementing CTS Operations Normal Unload Button If the CTS’s EEPROM image includes the “normal” unload button setting (default), the following actions occur when you press the unload button. (These steps assume that a data cartridge is loaded and that the CTS is ready.) Note: If you have prevented media removal with a PREVENT/ ALLOW MEDIUM REMOVAL command, the CTS performs no action when you press the unload button. 1. Any command or operation currently in progress is completed. 2.
3 Implementing CTS Operations 3. The tape is rewound to the physical beginning of tape (PBOT). 4. The tape is unloaded from the tape path. 5. The data cartridge is ejected. CAUTION When you use the “fast” version of the unload button to unload the tape, the data in any partially transmitted logical blocks is lost (not put on tape for a write operation or not sent to the initiator for a read operation).
3 Implementing CTS Operations 5. The data cartridge is ejected. 6. The CTS is reset. CAUTION • Since the tape is not rewound when you use the “super fast” version of the unload button, the tape is unloaded from the CTS at its current position. If the unload occurs when the tape is positioned over data, tape damage and data loss can occur.
3 Implementing CTS Operations Status Reported for Unload Procedure If a command is issued to the CTS during the unload procedure, the CTS returns Check Condition status with the sense key set to Unit Attention (6h). Once the Unit Attention condition is reported, all subsequent commands (except INQUIRY and REQUEST SENSE) receive Check Condition with the sense key set to Not Ready (2h). (For information about clearing a Unit Attention condition, see Section 3.9.
3 Implementing CTS Operations 3.2 Controlling the Format of Data on the Tape As described in Chapter 1, the EXB-8505 reads and writes tapes in four logical formats: 8500c, 8500, 8200c, and 8200. The EXB-8205 reads and writes tapes in two logical formats: 8200c and 8200. You control the format of the tape by issuing a MODE SELECT (15h) command when the tape is positioned at the logical beginning of tape (LBOT). Keep the following rules in mind whenever you write, append to, or read a tape.
3 Implementing CTS Operations 3.3 Using Data Compression When writing in either 8200c or 8500c format, the CTS uses the Improved Data Recording Capability (IDRC) compression algorithm licensed from IBM. During compression, the CTS uses the Exabyte Compression Integrity Check feature to ensure that data is accurately compressed and decompressed into the original form sent by the initiator. When the CTS writes data to tape in compressed format, it compresses the data at an average ratio of 2:1.
3 Implementing CTS Operations Using the EXB-8505 to Write Compressed Data The EXB-8505 writes compressed data in two different formats: 8200c and 8500c. The default data format for the EXB-8505 is typically 8500c. However, an EEPROM option allows you to choose whether the default data format is 8200, 8200c, 8500, or 8500c (see the “Default write format” option on page A-5).
3 Implementing CTS Operations Using the EXB-8205 to Write Compressed Data The EXB-8205 writes compressed data in 8200c format only. The default data format for the EXB-8205 is typically 8200c. However, an EEPROM option allows you to choose whether the default data format is 8200c or 8200 (see the “Default write format” option on page A-5). When writing compressed data with the EXB-8205, keep the following rules in mind: The EXB-8205 allows only one physical format on any one tape.
3 Implementing CTS Operations 3.4 Setting the Size of Data Blocks You may want to adjust the block size of the data being transferred from the host to the CTS to use the maximum capacity of the data cartridge. If you are writing data to tape in 8200 format, block-size optimization is particularly important.
3 Implementing CTS Operations 3. The third physical block written to tape contains 1,024 bytes of data from the host. 4. The fourth physical block contains 512 bytes of host data and 512 gap bytes. 5. The pattern is repeated until all of the logical blocks are written. Because the block size (1,536 bytes) is not an exact multiple of 1,024, tape capacity is reduced by the addition of gap bytes. In this case, approximately one-fourth of the available tape capacity is wasted.
3 Implementing CTS Operations Example In an extreme case, suppose that the host is sending a series of one-byte logical blocks to the CTS. Tape capacity is used as follows: 1. The CTS places the first two one-byte data blocks in the 1,024-byte physical block. No header information is added to these blocks. This consumes two bytes of space in the physical block. 2.
3 Implementing CTS Operations 3.5 Using Filemarks and Setmarks Filemarks and setmarks enable an initiator to locate particular blocks of data using high-speed search. When writing data to tape, an initiator can use WRITE FILEMARKS commands to write filemarks or setmarks (8500c format only) to indicate data boundaries.
3 Implementing CTS Operations Note: The short filemark in 8200 format is equivalent to the alternate short filemark written by the EXB-8200SX. Refer to the EXB-8200SX 8mm Cartridge Tape Subsystem Product Specification and User’s Manual for more information. Summary of Filemark Sizes As described in Table 3-3, the size of the filemarks that can be written depend on the format of the tape and on the setting of the Short bit in the WRITE FILEMARKS (10h) command (see Chapter 27).
3 Implementing CTS Operations 3.6 Using Streaming vs. Start/Stop Mode The CTS includes a 1-MByte data buffer that enables it to operate as either a streaming tape device or as a start/stop tape device, depending on the rate of data transfer to and from the host system. If your system permits, operating the CTS in streaming mode can maximize the amount of data you can store on a tape and minimize the amount of wear on the tape and recording heads.
3 Implementing CTS Operations Start/stop activity increases the amount of wear on the tape and the CTS’s recording heads. It also decreases the amount of data that can be stored on the tape because gap blocks and gap tracks are written to the tape whenever tape motion has to be stopped. Matching Host and CTS Data Transfer Rates Table 3-4 shows the data transfer rates that must be achieved to enable the CTS to operate in streaming mode.
3 Implementing CTS Operations Using the Motion Threshold and Reconnect Threshold This section explains how to increase the efficiency of data transfers to and from the CTS’s buffer by adjusting the motion threshold and reconnect threshold. Although start/stop operations are not as efficient as streaming operations, you can maximize start/stop performance by adjusting the motion threshold. You can maximize streaming performance by adjusting the reconnect threshold.
3 Implementing CTS Operations Motion Threshold The motion threshold is used in start/stop mode to control data transfers between the buffer and the tape. The motion threshold is measured in 4-KByte increments. The default is 80h (512 KBytes). This value represents half the capacity of the CTS’s buffer. You can change the motion threshold value with a MODE SELECT (15h) command.
3 Implementing CTS Operations Reconnect Threshold The reconnect threshold is used in streaming mode to control data transfers between the buffer and the initiator. The reconnect threshold is measured in 3-KByte increments. The default value is 80h (384 KBytes). You can change this value with a MODE SELECT (15h) command. Write Operations During a streaming write operation, the CTS disconnects from the initiator when the buffer becomes full but continues to write data to tape.
3 Implementing CTS Operations Summary of Motion and Reconnect Thresholds Table 3-6 provides summary information about the motion and reconnect thresholds. Table 3-6 Motion threshold and reconnect threshold summary Default value Motion Threshold Reconnect Threshold 80h in 4-KByte increments (512 KBytes) 80h in 3-KByte increments (384 KBytes) What it represents during a write operation... What it represents during a read operation...
3 Implementing CTS Operations 3.7 Formatting and Using Partitions (EXB-8505) In 8500c format, the EXB-8505 can write and read tapes containing either one or two partitions. Partitioned tapes provide a highly efficient way to maintain a directory at the beginning of a tape. This directory can indicate where various data sets are located on the tape and can include the following types of information: The names of the data sets on the tape.
3 Implementing CTS Operations Each partition on a tape contains a logical and physical beginning (LBOP and PBOP) and a logical and physical end (LEOP and PEOP). The EXB-8505 considers each partition a completely self-contained recording area independent of the other partition on the tape. The EXB-8505 cannot move the tape beyond the beginning or end of a partition unless specifically requested to by a LOCATE (2Bh) or MODE SELECT (15h) command.
3 Implementing CTS Operations As shown in Figure 3-1, the first partition on a dual-partition tape is Partition 1, and the second partition is Partition 0. For a dual-partition tape, the following areas correspond: The physical beginning of the tape (PBOT) is equivalent to the physical beginning of the first partition (PBOP 1). The logical beginning of the tape (LBOT) is equivalent to the logical beginning of the first partition (LBOP 1).
3 Implementing CTS Operations 1. Load a tape into the EXB-8505, or rewind the current tape to the logical beginning of tape (LBOT). The tape must be positioned at LBOT or at the logical beginning of a partition (LBOP) before you can format the tape with new partitions. 2. Make sure that the EXB-8505 is set to write in 8500c format. If necessary, issue a MODE SELECT command with the Density Code in the Block Descriptor set to 8Ch. 3. Issue a MODE SELECT command and specify page format (PF=1).
3 Implementing CTS Operations How Do You Use a Dual-Partition Tape? The easiest way to understand how to use a dual-partition tape is to think of it as two separate tapes. Just as you would have to physically change tapes to access data on a second tape, you have to specifically request that the tape be moved to the other partition before you can perform actions in that partition. The following are descriptions of how to perform several typical actions on a dual-partition tape.
3 Implementing CTS Operations Changing Partitions If you want to move the tape from one partition to the logical beginning of the other partition (LBOP), use the LOCATE command with the following parameters: Set CP (Change Partitions) to 1 to indicate you want to change partitions. For Block Address, specify the block you want the tape to be located to. Set Partition to 0 if you want the tape located in the second partition or 1 if you want the tape located in the first partition.
3 Implementing CTS Operations Writing Data in Partitions To write data, use the WRITE (0Ah) command as you would with a standard tape. However, remember that if you want to write data in the partition the tape is not currently in, you must first use the MODE SELECT command to indicate that you want to change partitions. The EXB-8505 repositions the tape to the new partition after it receives a tape motion command such as SPACE (11h).
3 Implementing CTS Operations Reading Data on a Partitioned Tape To read data, use the READ (08h) command as you would with a standard tape. However, remember that if you want to read data in the partition the tape is not currently in, you must use the LOCATE or MODE SELECT command to reposition the tape to that partition. After you have issued a command to relocate to a new partition, you can use a LOCATE command or SPACE command to move the tape to a legal position for reading data.
3 Implementing CTS Operations Important When you reformat a dual-partition tape to create a single-partition tape, all of the information defining the original two partitions is erased. However, the data on the tape is not erased. For this reason, if you are concerned about data remaining on a tape, do not use reformatting as a way to erase data. You must explicitly perform an erase operation to erase the data.
3 Implementing CTS Operations 3.9 Handling Unit Attention Conditions The CTS creates a Unit Attention condition for each initiator when any of the following conditions occurs: The CTS is reset (whether by a Bus Device Reset message, a SCSI bus reset, or a power-on reset). The MODE SELECT parameters are changed by an initiator other than the one attempting to communicate with the CTS. The unload button is pressed and the data cartridge is ejected. A data cartridge is inserted and automatically loaded.
3 Implementing CTS Operations When you insert a data cartridge into the CTS, the CTS returns Check Condition status with the sense key set to Unit Attention (6h). However, if you insert a data cartridge and autoloading is prevented (that is, autoload was disabled with a MODE SELECT command and a LOAD (1Bh) command was not received), the CTS returns Check Condition status with the sense key set to Not Ready (2h).
3 Implementing CTS Operations 3.10 Resetting the CTS You can use any of the following methods to reset the CTS: Power the CTS off and back on again (power-on reset). If a servo or hardware error has occurred, press the unload button to clear the error and reset the CTS. (Then, if necessary, wait a few seconds and press the button again to eject the tape.) Send a RST pulse on the SCSI bus for a minimum of 25 µsec (SCSI bus reset).
3 Implementing CTS Operations Effect of SCSI Bus and Device Resets SCSI bus and device resets have the following effects: If the CTS is connected to the SCSI bus, the SCSI bus goes to the Bus Free phase. The servo is reset and a servo self-test is performed. All CTS parameters are reset to their default states. A test of the microprocessor’s external memory is performed. After a SCSI bus or device reset, the CTS will respond on the SCSI bus within 250 msec.
3 Implementing CTS Operations Reset Processing This section specifies how the CTS processes power-on resets, SCSI bus resets, and device resets. The CTS processes resets differently depending on whether a data cartridge is present or not. Data Cartridge Present before Reset If a data cartridge is present before the reset occurs, the tape is rewound, unloaded, and reloaded. When the reset is complete, the tape is positioned at LBOT and the CTS is ready to process tape motion commands.
3 Implementing CTS Operations Data Cartridge Not Present before Reset When a data cartridge is not present, the CTS responds to the reset as follows: It returns Check Condition status to the first command received. The sense key is set to Unit Attention (6h), and the ASC and ASCQ fields indicate that a reset occurred. It processes all non-motion commands. The TEST UNIT READY (00h) command returns Check Condition status with the sense key set to Not Ready (2h).
3 Implementing CTS Operations Notes: 3-38 EXB-8205 and EXB-8505 (Standard and XL) 510503
4 ERASE (19h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 1 0 0 1 01 Logical Unit Number Immed Long 0 0 Reserved 02 Reserved 03 04 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 4-1
4 ERASE (19h) 4.1 About This Command The ERASE command causes the CTS to erase all tape from the current valid tape position to the physical end of tape (PEOT). When the erase operation is successfully completed, the tape is automatically rewound to the logical beginning of tape (LBOT). The ERASE command performs the erase operation at the same speed as the READ and WRITE commands are performed; for example, starting at LBOT, a 112m EXATAPE data cartridge will take approximately two hours to erase.
4 ERASE (19h) 4.2 Field Definitions Byte 01, Bit 1 - Immed The Immed bit is used to determine when command status is returned to the initiator, as follows: 0 – Status is reported to the initiator when the ERASE command is completed. 1 – Status is reported to the initiator when the ERASE command is initiated by the CTS.
4 ERASE (19h) 4.3 Tape Positioning Table 4-1 shows the legal tape positions for an erase operation in the data formats supported by the EXB-8505 and EXB-8205. Table 4-1 Legal locations for performing an erase operation When erasing a tape written in this format... You can erase from the following locations...
5 INQUIRY (12h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 0 1 0 01 Logical Unit Number Reserved 02 Page Code 03 Reserved 04 Allocation Length 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) EVPD 0 0 5-1
5 INQUIRY (12h) 5.1 About This Command The INQUIRY command requests that information about the CTS’s parameters be sent to the initiator. The CTS executes the INQUIRY command whether a tape is loaded and whether it has been reserved by another initiator. The CTS will return inquiry data within 3 seconds of a power cycle or when a Unit Attention condition exists. Issuing an INQUIRY command does not clear a pending Unit Attention for the initiator. 5.
5 INQUIRY (12h) Byte 04 - Allocation Length The Allocation Length specifies the number of bytes that the initiator has allocated for the return of inquiry data. A value of 0 indicates that no inquiry data is to be transferred and is not an error. The CTS terminates the Data In phase when the number of bytes specified in the Allocation Length field has been transferred or when all available inquiry data has been transferred, whichever is less.
5 INQUIRY (12h) 5.3 Standard Inquiry Data The CTS returns the Standard Inquiry Data when the EVPD bit in the CDB is 0.
5 INQUIRY (12h) Byte 00, Bits 7 through 5 - Peripheral Qualifier This field, in combination with the Peripheral Device Type field (byte 00, bits 4 through 0), identifies the device currently connected to the logical unit. The value returned for this field is 0, which indicates that the specified device is currently connected to the selected logical unit. If the LUN in the CDB or in the Identify message is not 0, the value returned for these fields is 7Fh, which indicates that the LUN is invalid.
5 INQUIRY (12h) Byte 03, Bit 6 - TrmIOP The value returned for this field is 0, which indicates that the CTS does not support the Terminate I/O Process message. Byte 03, Bits 3 through 0 - Response Data Format The value returned for this field is 2h, which indicates that the data found is in accordance with the ANSI SCSI-2 standard.
5 INQUIRY (12h) Byte 07, Bit 0 - SftRe The value returned for this field is 0, which indicates that the CTS does not support the soft reset alternative in response to a reset condition. Bytes 08 through 15 - Vendor Identification The value contained in these bytes are the ASCII representation of “EXABYTE”, followed by a single space. By using an EEPROM option, the values for these bytes may be customized for specific requirements (see the “Vendor ID” option on page A-10).
5 INQUIRY (12h) 5.4 Supported Vital Product Data Page The CTS returns the Supported Vital Product Data page when the EVPD bit in the CDB is 1 and the Page Code is 0. Bit Byte 00 7 6 5 4 Peripheral Qualifier 3 2 1 0 Peripheral Device Type 01 Page Code 02 Reserved 03 Page Length 04 First Page Code Supported 05 Second Page Code Supported Byte 00, Bits 7 through 5 - Peripheral Qualifier The value for this field is 0, indicating that this is a single LUN device.
5 INQUIRY (12h) 5.5 Unit Serial Number Page The CTS returns the Unit Serial Number page when the EVPD bit in the CDB is 1 and the Page Code is 80h. Bit Byte 7 6 5 4 3 00 Device Type Code 01 Page Code 02 Reserved 03 Page Length 2 1 0 … 04 Unit Serial Number 13 Byte 00 - Device Type Code The value returned for this field is 01h, which identifies the CTS as a sequential access device. If the LUN in the CDB is not 0, the value returned is 7Fh, which indicates that the LUN is invalid.
5 INQUIRY (12h) Notes: 5-10 EXB-8205 and EXB-8505 (Standard and XL) 510503
6 LOAD/UNLOAD (1Bh) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 1 0 1 1 01 Logical Unit Number Reserved 02 Immed Reserved 03 04 05 May 1994 Reserved Vendor Unique EOT Reserved EXB-8205 and EXB-8505 (Standard and XL) Re-Ten Load 0 0 6-1
6 LOAD/UNLOAD (1Bh) 6.1 About This Command The LOAD/UNLOAD command causes the CTS to load or unload the data cartridge. Loading a Data Cartridge When loading a data cartridge, the CTS performs the following actions: 1. Loads the tape in the tape path. 2. Positions the tape to the logical beginning of tape (LBOT).
6 LOAD/UNLOAD (1Bh) Using the LOAD/UNLOAD Command on a Partitioned Tape When the tape you are using is formatted with two partitions (see Section 3.7), the LOAD/UNLOAD command performs as follows.
6 LOAD/UNLOAD (1Bh) 6.2 Field Definitions Byte 01, Bit 1 - Immed The Immed bit is used to determine when command status is returned to the initiator, as follows: 0 – Status is reported to the initiator when the load/unload operation is complete. 1 – Status is reported to the initiator when the command is initiated by the CTS.
6 LOAD/UNLOAD (1Bh) Byte 04, Bit 0 - Load The Load bit indicates which operation, load or unload, is to be performed as follows: 0 – Perform an unload operation. 1 – Perform a load operation. Table 6-1 indicates what action occurs based on the setting of the Load bit and the status of the data cartridge: Table 6-1 Action occurring based on Load bit and data cartridge status If the Load bit is set to... And the data cartridge is... 0 Out 1 Out 0 In The following action occurs... No action.
6 LOAD/UNLOAD (1Bh) Notes: 6-6 EXB-8205 and EXB-8505 (Standard and XL) 510503
7 LOCATE (2Bh) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 1 0 1 0 1 1 01 Logical Unit Number BT CP Immed 02 Reserved (MSB) … 03 Reserved Block Address 06 (LSB) 07 Reserved 08 Partition 09 May 1994 ADE VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 7-1
7 LOCATE (2Bh) 7.1 About This Command The LOCATE command, in conjunction with the READ POSITION (34h) command, allows you to position the tape at a specified logical block address. During forward and backward locate operations, the CTS moves the tape at its high-speed search speed, which is up to 75 times the nominal tape speed. Unlike space operations, locate operations do not detect filemarks and setmarks (8500c format only) and do not return Check Condition status when these elements are encountered.
7 LOCATE (2Bh) Notes: The LOCATE command is not supported for tapes written in 8200 format and will result in Check Condition status. The sense key will be set to Illegal Request (5h). If the disconnect option is enabled, the CTS can disconnect from the initiator while the LOCATE command is executing.
7 LOCATE (2Bh) 7.2 Field Definitions Byte 01, Bit 2 - BT (Block Type) The BT bit determines the type of block number contained in the Block Address field (bytes 03 through 06), as follows: 0 – The Block Address field contains the SCSI logical block number, numbered sequentially from the beginning of the tape (or the beginning of the partition for a dual-partition tape in 8500c format). 1 – The Block Address field contains an Exabyte-unique block address (currently not implemented).
7 LOCATE (2Bh) If the CTS buffer contains data from a previous WRITE command and the LOCATE command is in the reverse direction, the CTS disconnects from the initiator (if disconnect was enabled by the Identify message) and writes the data in the buffer to the tape. If the Immed bit is set to 1, the CTS reconnects to the initiator when the write operation has completed successfully. It then returns Good status and performs the locate operation.
7 LOCATE (2Bh) Byte 09, Bit 7 - ADE (Always Detect EOD) The ADE bit is used only for those CTSs that include the EEPROM image for directory support (see the “Allow position past EOD” option on page A-21). This bit is ignored if the CTS does not include the directory support feature. The ADE bit is also ignored if the tape loaded in the CTS contains two partitions (EXB-8505 with a tape in 8500c format).
7 LOCATE (2Bh) 7.3 Exceptions and Error Conditions The following exceptions and error conditions can occur with the LOCATE command. EOD Detected If the CTS detects the end-of-data (EOD) mark during the locate operation, it returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 1 Sense Key Blank Check (8h) Information bytes Indicate the difference between the requested logical position and the actual logical position.
7 LOCATE (2Bh) PEOT or PEOP Encountered During a locate operation, if the CTS encounters the physical end of tape (PEOT) or the physical end of partition (8500c format only), it returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 0 or 1 EOM 1 Sense Key Medium Error (3h) Information bytes If Valid=1, indicate the difference between the requested logical position and the last logical position detected.
7 LOCATE (2Bh) Unrecoverable Error If an unrecoverable media or hardware error occurs during the locate operation, the CTS terminates the LOCATE command and returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 0 or 1 Sense Key Medium Error (3h) or Hardware Error (4h) Information bytes If Valid=1, indicate the difference between the requested logical position and the actual logical position.
7 LOCATE (2Bh) Notes: 7-10 EXB-8205 and EXB-8505 (Standard and XL) 510503
8 LOG SELECT (4Ch) Bit Byte 7 6 5 4 3 2 1 0 00 0 1 0 0 1 1 0 0 01 Logical Unit Number PCR SP 02 Reserved PC Reserved … 03 Reserved 06 07 (MSB) Parameter List Length 08 09 May 1994 (LSB) Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 8-1
8 LOG SELECT (4Ch) 8.1 About This Command The LOG SELECT command allows you to manage the counters that the CTS maintains about its write and read error recovery operations.
8 LOG SELECT (4Ch) Figure 8-1 Relationship of log parameters and parameter lists to the LOG SELECT CDB May 1994 EXB-8205 and EXB-8505 (Standard and XL) 8-3
8 LOG SELECT (4Ch) 8.2 Field Definitions Byte 01, Bit 1 – PCR (Parameter Code Reset) The PCR bit indicates whether you want to set some or all of the counters, as follows: 0 – Set some of the counters only, as indicated by the PC field. 1 – Reset all of the counters. Current cumulative values will be reset to 0, the Enable Threshold Comparison (ETC) bit will be reset to 0 (see page 8-10), and threshold values will be reset to all FFs.
8 LOG SELECT (4Ch) Byte 02, Bits 5 through 0; Bytes 03 through 06 – Reserved These bits and bytes are reserved. Bytes 07 and 08 – Parameter List Length The Parameter List Length field indicates the number of bytes in the parameter lists that the initiator will send during the Data Out phase. The Parameter List Length must equal the sum of the lengths for each log parameter plus four bytes for each Parameter List Header. If a parameter list is transferred, it must be transferred in its entirety.
8 LOG SELECT (4Ch) 8.3 Parameter List Header The Parameter List Header is sent during the Data Out phase before the log parameters. More than one Parameter List Header can be sent with each LOG SELECT command. Bit Byte 00 7 6 5 4 Reserved 2 1 0 Page Code 01 02 3 Reserved (MSB) Page Length 03 (LSB) Byte 00, Bits 7 and 6 – Reserved These bits are reserved. Byte 00, Bits 5 through 0 – Page Code The Page Code field indicates the code of the log parameter page you want to modify.
8 LOG SELECT (4Ch) 8.4 Log Parameters Zero or more log parameters follow the Parameter List Header. Each log parameter includes four bytes of descriptive information followed by a variable-length parameter value. There is no required order for the log parameters.
8 LOG SELECT (4Ch) Table 8-2 Parameter Codes for LOG SELECT command Parameter Code Counter Name Total Rewrites Total Rereads 0004h Write Error Counter Page. Contains the number of physical blocks the CTS rewrote to the tape because of errors detected during read-after-write operations. Only user data blocks and short filemark blocks are ever rewritten. Note: This counter is equivalent to the Total Errors Corrected counter.
8 LOG SELECT (4Ch) Byte 02, Bit 7 – Disable Update (DU) The DU bit indicates whether updates to the current cumulative value are enabled or disabled, as follows: 0 – The CTS can update the current cumulative value, so comparisons of the current cumulative value and the threshold value can occur normally. 1 – The CTS will not update the current cumulative value, so threshold conditions will not be met for this counter.
8 LOG SELECT (4Ch) Byte 02, Bit 4 – Enable Threshold Comparison (ETC) The ETC field indicates whether threshold comparisons for the counter are enabled or disabled, as follows: 0 – Threshold comparisons for this counter are disabled. 1 – Threshold comparisons are performed on this counter. If threshold comparisons are enabled, the CTS compares the cumulative value to the threshold value when the cumulative value is updated.
8 LOG SELECT (4Ch) Byte 03 – Parameter Length The Parameter Length field indicates the length of the threshold or cumulative value in bytes. For example, if the value requires two bytes, you would specify 02h for this field. Table 8-3 lists the length of each counter.
8 LOG SELECT (4Ch) 8.5 Exceptions and Error Conditions The following exceptions and error conditions can occur with the LOG SELECT command. Illegal Value in LOG SELECT Data If one of the bytes sent with the LOG SELECT data contains an illegal value or if a reserved bit is set, the CTS returns Check Condition status. To determine which byte contains the error, issue a REQUEST SENSE command.
8 LOG SELECT (4Ch) Table 8-4 REQUEST SENSE data for LOG SELECT errors and exceptions FSC Sense Key ASC ASCQ CAh 6h 5Bh 01h CBh 6h 2Ah 02h ECh 1h 5Bh 02h Description Unit Attention. Threshold met. (For additional information about this error, look at the Log Parameter Page Code and Log Parameter Code bytes in the REQUEST SENSE data.) Unit Attention. Log parameter changed. Recovered Error. Log parameter overflow (a cumulative counter reached its maximum value of all FFs).
8 LOG SELECT (4Ch) Notes: 8-14 EXB-8205 and EXB-8505 (Standard and XL) 510503
9 LOG SENSE (4Dh) Bit Byte 7 6 5 4 3 2 1 0 00 0 1 0 0 1 1 0 1 01 Logical Unit Number PPC SP 02 PC 03 Reserved Page Code Reserved 04 05 (MSB) Parameter Pointer 06 07 (LSB) (MSB) Allocation Length 08 09 May 1994 (LSB) Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 9-1
9 LOG SENSE (4Dh) 9.1 About This Command The LOG SENSE command enables you to retrieve statistical information about the CTS’s read and write error recovery operations.
9 LOG SENSE (4Dh) Byte 02, Bits 7 and 6 – PC (Page Control) The PC field indicates what type of parameter values you want the CTS to return. Valid values for this field are as follows: 00b – Return the current threshold values. These values are reset to their default settings after a power-on reset, SCSI bus reset, or Bus Device Reset message. In addition, the initiator can issue a LOG SELECT (4Ch) command to set these values. 01b – Return the current cumulative values.
9 LOG SENSE (4Dh) Bytes 05 and 06 – Parameter Pointer The Parameter Pointer field indicates the Parameter Code of the first counter you want to be returned for the requested page. As long as the value in the Allocation Length field is large enough, the CTS returns all counters with a Parameter Code greater than or equal to the code specified in this field. For example, if you specify 0004h for the Parameter Pointer, the CTS returns information about counters 0004h through 0006h.
9 LOG SENSE (4Dh) 9.3 Parameter List Header The four-byte Parameter List Header precedes each of the LOG SENSE pages. It specifies a page code and indicates the total length of the data to follow. Bit Byte 7 6 00 0 0 5 4 2 1 0 Page Code 01 02 3 Reserved (MSB) Page Length 03 (LSB) Byte 00, Bits 5 through 0 – Page Code The Page Code field identifies the type of LOG SENSE data being returned by the CTS.
9 LOG SENSE (4Dh) 9.4 Supported Log Pages Page (Page Code=00h) The Supported Log Pages page is returned when the Page Code in the CDB is 00h. Unlike other LOG SENSE pages, no parameter information is returned on this page. Instead, the Supported Log Pages page lists the LOG SENSE pages supported by the CTS. The page codes are listed in ascending order.
9 LOG SENSE (4Dh) 9.5 Log Parameter Data Blocks (Page Codes=02h and 03h) When the Page Code is 02h or 03h, the CTS returns information about its log parameters (counters) immediately after it returns the Parameter List Header. For each counter, the CTS returns a data block that includes four bytes of descriptive information and a variable-length parameter value. The total number of bytes returned for each counter is equal to the value for the Parameter Length field plus four.
9 LOG SENSE (4Dh) Byte 0, Bit 7 – DU (Disable Update) The value returned for the Disable Update field indicates whether updates to the current cumulative value for this counter are enabled or disabled, as follows: 0 – The CTS can update the current cumulative value, so comparisons between the current cumulative value and the threshold value occur normally. 1 – The CTS will not update the current cumulative value, so threshold conditions will not be met for this counter.
9 LOG SENSE (4Dh) Byte 02, Bits 3 and 2 – TMC (Threshold Met Criteria) The value returned for the TMC bit specifies the conditions under which the CTS will generate a Unit Attention (6h) sense key when comparing the current cumulative value to the threshold value. Threshold comparisons are made when the cumulative value is updated.
9 LOG SENSE (4Dh) Write Error Counters Page (Page Code=02h) When you specify 02h for the Page Code, the CTS returns information about the counters listed in Table 9-1.
9 LOG SENSE (4Dh) Total Bytes Processed The Total Bytes Processed counter contains the number of bytes successfully written to the tape. This counter only includes user data bytes, the gap bytes in user data blocks, and the bytes in short filemark blocks. Rewritten data is not counted. Total Unrecoverable Errors The Total Unrecoverable Errors counter contains the number of times the CTS could not write a block to the tape.
9 LOG SENSE (4Dh) Total Bytes Processed The Total Bytes Processed counter contains the number of user data bytes transferred to the initiator. Rewritten data is not counted. Total Unrecoverable Errors The Total Unrecoverable Errors counter contains the number of blocks the CTS could not read after exhausting all retries.
10 MODE SELECT (15h) and MODE SENSE (1Ah) This chapter describes the bit and byte settings for both the MODE SELECT and MODE SENSE commands. It consists of separate sections defining the CDB and Parameter List Header fields for the two commands, followed by combined sections for the Block Descriptor, Vendor-Unique Parameters, and parameter pages that are common to both commands.
10 MODE SELECT (15h) and MODE SENSE (1Ah) MODE SELECT (15h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 1 0 1 01 Logical Unit Number PF 02 Reserved SP Reserved 03 04 05 Parameter List Length Vendor Unique Reserved 0 0 MODE SENSE (1Ah) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 1 0 1 0 01 Logical Unit Number RSVD DBD 02 Page Code 03 Reserved 04 Allocation Length 05 10-2 PC Vendor Unique Reserved Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 510503
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.1 About These Commands The MODE SELECT command allows the initiator to specify medium, logical unit, and device parameters. The MODE SENSE command enables the CTS to report these parameters to the initiator. These values apply to all initiators in a multi-initiator environment. MODE SELECT and MODE SENSE parameters can be structured in either of two formats: non-page format or page format.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.2 Field Definitions for MODE SELECT CDB Byte 01, Bit 4 - PF (Page Format) The PF bit indicates in which format the MODE SELECT parameters are specified, as follows: 0 – Parameters after the Block Descriptor are vendor specific (non-page format) 1 – Parameters after the Block Descriptor are structured as pages of related parameters (page format) Byte 01, Bit 0 - SP (Saved Page) The CTS does not support the saved page function. The valid value for this bit is 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Page Format For page format, the value of the Parameter List Length byte depends on which combination of parameter pages is being transferred. Table 10-2 shows the number of bytes that should be designated to transfer the various types of MODE SELECT parameters. Table 10-2 MODE SELECT Parameter List Lengths (page format) To transfer these parameters... Designate this amount...
10 MODE SELECT (15h) and MODE SENSE (1Ah) Example 2 To transfer the Parameter List Header, the Block Descriptor, and the Data Compression Page: 1. Specify 1Ch for the Parameter List Length byte (04h for the Parameter List Header + 08h for the Block Descriptor + 10h for the Data Compression Page). 2. Set the Block Descriptor Length byte in the Parameter List Header to 08h. Example 3 To transfer the Parameter List Header, the Block Descriptor, and the Vendor Unique Parameters Page 1: 1.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Restrictions for Sending MODE SELECT Parameters: For non-page format, valid transfer lengths for the vendor-unique parameters are 0, 1, 2, 3, 4, and 5 bytes. All transfers of the vendor-unique parameters start with byte 0. For data transfers greater than 0 bytes, the entire 4-byte Parameter List Header must be transferred before the Block Descriptor or any parameter pages or vendor-unique parameters.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.3 Field Definitions for MODE SENSE CDB Byte 01, Bit 3 - DBD (Disable Block Descriptor) The Disable Block Descriptor bit indicates whether the initiator wants the 8-byte Block Descriptor returned as part of the MODE SENSE parameter data. This bit is defined as follows: 0 – Send the Block Descriptor 1 – Do not send the Block Descriptor Note: The DBD bit must be 0 if the Page Code is 0 (non-page format).
10 MODE SELECT (15h) and MODE SENSE (1Ah) Table 10-4 Values for the Page Code field in the MODE SENSE command To return the parameters in... Specify this Page Code...
10 MODE SELECT (15h) and MODE SENSE (1Ah) Page Format For page format, the Allocation Length byte can contain values ranging from 00h to FFh, depending on which parameter page is being returned and whether you want the Block Descriptor to be returned (that is, whether you set the DBD bit to 0 or 1) Table 10-6 shows the minimum values you can specify for the Allocation Length when the Page Code field is set to a non-zero value.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Example 1 To return the Parameter List Header, the Block Descriptor, and the Vendor Unique Parameters Page 1: 1. Set the DBD bit to 0. 2. Set the Page Code to 20h. 3. Specify at least 12h for the Allocation Length byte (04h for the Parameter List Header + 08h for the Block Descriptor + 06h for the Vendor Unique Parameters Page 1). Example 2 To return the Parameter List Header, the Block Descriptor, and the Data Compression Page: 1. Set the DBD bit to 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Truncating Pages An EEPROM option enables you to choose whether the Allocation Length is checked for values that would cause the Parameter List Header, Block Descriptor, or one of the parameter pages to be truncated. With the EEPROM option, you can choose to disallow or permit truncated pages (see the “MODE SELECT and MODE SENSE” option on page A-11).
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02, Bits 3 through 0 - Speed The CTS does not support any operations at different speeds. All operations have a defined speed that cannot be modified by this command. The valid value for this field is 0. Byte 03 - Block Descriptor Length This byte contains the length of the Block Descriptor in bytes. The CTS does not support multiple block descriptions. The valid values for this byte are 00h (for no Block Descriptor) and 08h (for the entire Block Descriptor).
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 01 - Medium Type The value returned in the Medium Type byte represents the length of tape currently loaded in the CTS. The values that can be returned are shown in Table 10-7.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02, Bits 6 through 4 - Buffered Mode Indicates whether the CTS buffers data during a write operation, as explained on page 10-13. The values returned are as follow: 000b – Unbuffered mode. 001b – Buffered mode (power-on default). Byte 02, Bits 3 through 0 - Speed The CTS does not support any operations at different speeds. All operations have a defined speed that cannot be modified. The value returned for this field is 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.6 Block Descriptor Bit Byte 7 6 00 01 5 4 3 2 0 Density Code (MSB) Number of Blocks 02 03 (LSB) 04 05 1 Reserved (MSB) Block Length 06 07 (LSB) Byte 00 - Density Code In the MODE SELECT command, the Density Code field specifies the format in which you want the CTS to write data to tape. In the MODE SENSE command, the Density Code field identifies the current operating density of the CTS. Table 10-8 lists the valid values for the Density Code.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Table 10-8 Values for the Density Code field Specify this Density Code... To write data in this format Notes Use this Density Code at LBOT if you want to write default format tapes (8500c for the EXB-8505; 8200c for the EXB-8205)*.
10 MODE SELECT (15h) and MODE SENSE (1Ah) As described in Table 10-9, the value reported for the Density Code field by the MODE SENSE command depends on the most recent activity. Table 10-9 Effect of various actions on the Density Code reported by MODE SENSE ...then the value reported for the Density Code is the... If the most recent activity was a... ... actual format of the data on the tape (format for reading tape) Power on (tape not loaded) ...
10 MODE SELECT (15h) and MODE SENSE (1Ah) Bytes 01 through 03 - Number of Blocks In the MODE SENSE data, this field indicates the total capacity of the tape in 1-KByte physical blocks (LBOT to LEOT). The CTS determines this value when it loads a tape. This field is ignored by the CTS in the MODE SELECT command. Bytes 05 through 07 - Block Length The Block Length field defines the length in bytes of each logical block, in uncompressed format, described by the Block Descriptor.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.7 Vendor-Unique Parameters (Non-Page Format) Bit Byte 7 6 5 4 3 2 1 0 00 CT RSVD ND RSVD NBE EBD PE NAL 01 Reserved 02 Motion Threshold 03 Reconnect Threshold 04 Gap Threshold 112m Byte 00, Bit 7 - CT (Cartridge Type) The CT bit works in conjunction with the 112m bit (byte 01, bit 0) to indicate the size of the data cartridge that is expected to be loaded in the CTS.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 00, Bit 5 - ND (No Disconnect During Data Transfer) This bit is used to enable the CTS to disconnect from the initiator during the data transfer phase, as follows: 0 – The CTS can disconnect during the data transfer phase. (Power-on default) 1 – The CTS will not disconnect during the data transfer phase.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 00, Bit 1 - PE (Parity Enable) This bit is used to enable parity checking on the SCSI bus. When this bit is set to 1, every byte received by the CTS is checked for parity. 0 – Parity checking disabled. 1 – Parity checking enabled. (Power-on default) Byte 00, Bit 0 - NAL (No Auto Load) This bit is used to disable the automatic loading of the tape into the tape path when a data cartridge is inserted into the CTS, as follows: 0 – Auto loading enabled.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 03 - Reconnect Threshold The value in the Reconnect Threshold byte indicates the amount of data that must be in the buffer before the CTS reconnects to the initiator for a buffered write or read operation. The value is expressed in 3-KByte increments. The default is 80h (384 KBytes). Valid values range from 20h to D0h (96 to 624 KBytes). For more information about the reconnect threshold, see Section 3.6.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.8 Read-Write Error Recovery Page (Page Code=01h) The Read-Write Error Recovery Page specifies error recovery parameters used during read-write operations. Bit Byte 00 7 6 5 03 3 Reserved 2 1 0 DTE DCR Page Code 01 02 4 Page Length Reserved TB RSVD EER PER Read Retry Count … 04 Reserved 07 08 Write Retry Count Byte 00, Bits 5 through 0 - Page Code The Page Code identifies the page being transferred.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02, Bit 0 - DCR (Disable Correction) The DCR bit is not supported by the CTS. The valid value is 0. Byte 03 - Read Retry Count The Read Retry Count field specifies how many times the CTS should attempt its read recovery algorithms before an unrecoverable read error is reported. If the CTS fails to reread the block after this number of attempts, it reports an unrecoverable read error. You can set the Read Retry Count to any value between 00h and 0Bh.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 08 - Write Retry Count The Write Retry Count field specifies how many times the CTS should rewrite a physical block before an unrecoverable write error is reported. The value for this field can only be changed when the tape is positioned at LBOT. The valid values for this field are 00h and 0Bh. The default value is 0Bh. Specify 00h for this field to set the Write Retry Count to 0. Specify any other nonzero value to set the Write Retry Count to 0Bh.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.9 Disconnect-Reconnect Page (Page Code=02h) The Disconnect-Reconnect Page specifies parameters for CTS disconnects and reconnects during data transfers.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02 - Buffer Full Ratio The Buffer Full Ratio represents the amount of data that must be present in the buffer during a buffered read operation before the CTS will attempt to reconnect to the initiator. The value is expressed in 3-KByte increments. The default value for the Buffer Full Ratio is 80h (384 KBytes). Valid values range from 20h to D0h (96 to 624 KBytes). The Buffer Full Ratio must equal the Buffer Empty Ratio (see below).
10 MODE SELECT (15h) and MODE SENSE (1Ah) Bytes 06 and 07 - Disconnect Time Limit The only value supported by the CTS for the Disconnect Time Limit field is 0. This value cannot be changed. Note: The disconnect time limit is determined by the minimum time it takes the CTS to disconnect from the SCSI bus and then initiate a reselection sequence. The minimum disconnect time for the CTS is 265 µsec. The initiator cannot change this field, so the value returned for this field by the MODE SENSE command is 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.10 Control Mode Page (Page Code=0Ah) The Control Mode Page allows you to specify whether the CTS should return Check Condition status when one of its write and read error counters reaches a specified threshold. For information about using the LOG SELECT command to set threshold values for the CTS’s write and read error counters, refer to Chapter 8.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 03, Bit 1 - QErr (Queue Error) The CTS does not support the Simple Queue Tag message, so this bit must be 0. Byte 03, Bit 0 - DQue (Disable Queuing) The CTS does not support the Simple Queue Tag message, so this bit must be 1. Byte 04, Bit 7 - EECA (Enable Extended Contingent Allegiance) The CTS does not support extended contingent allegiance, so this bit must be 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.11 Data Compression Page (Page Code=0Fh) The Data Compression Page specifies parameters for the control of data compression. Bit Byte 00 EXB-8505 For the EXB-8505, this page allows you to turn data compression on or off in 8500c format independently of the tape’s position. When the EXB-8505 writes data in 8200c format, the data is always compressed. Compression cannot be controlled by the user.
10 MODE SELECT (15h) and MODE SENSE (1Ah) EXB-8505 Only: Using the Data Compression Page for 8500c Compressed Format Tapes For the EXB-8505, if your driver uses page format and you are reading and writing 8500c compressed format tapes, follow these steps to control compression: 1. When the tape is at LBOT, set the Density Code in the Block Descriptor to 8Ch. This specifies 8500c format for the tape and turns data compression on. 2.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 01 - Page Length The Page Length indicates the number of bytes in the Data Compression Page that follow this byte. The valid value is 0Eh. Byte 02, Bit 7 - DCE (Data Compression Enable) The Data Compression Enable bit specifies whether the CTS should enable or disable data compression. When writing data in 8500c format with the EXB-8505, you can turn compression on or off using the DCE bit as follows: 0 – Disable data compression. 1 – Enable data compression.
10 MODE SELECT (15h) and MODE SENSE (1Ah) EXB-8205 For the EXB-8205, the DCE bit settings indicate the following: 0 – Data compression is disabled. The write density is set to 14h (8200 format). 1 – Data compression is enabled. The write density is set to 90h (8200c format). Byte 02, Bit 6 - DCC (Data Compression Capable) The Data Compression Capable bit is used by the MODE SENSE command to indicate that the CTS supports data compression. The value returned is 1.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Bytes 08 through 11 - Decompression Algorithm The Decompression Algorithm field indicates which decompression algorithm the CTS will use when decompressing data from the tape. The only value currently supported for this field is 10h (decompress data using the IDRC data compression algorithm). This is the only compression algorithm currently supported by the CTS.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 00, Bits 5 through 0 - Page Code The Page Code identifies the page being transferred. The valid value is 10h (Device Configuration Page). Byte 01 - Page Length The Page Length indicates the number of bytes in the Device Configuration Page that follow this byte. The valid value is 0Dh.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02, Bit 5 - CAF (Change Active Format) The CAF bit indicates that the active format is to be changed and to use the values in the Active Format field, as follows: 0 – Do not change active format. 1 – Change active format. In the MODE SENSE data, the value returned for this bit is always 0. Byte 02, Bits 4 through 0 - Active Format The Active Format field contains data that modifies the media format parameters.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 03 - Active Partition EXB-8505 If you have set the CAP bit (byte 02, bit 6) to 1 to change the active partition, the Active Partition byte indicates the number of the new partition that the tape is to be moved to, as follows: 0 – Move to the logical beginning (LBOP) of the second partition. 1 – Move to the logical beginning (LBOP) of the first partition. Notes: If the tape contains no partitions, the Active Partition byte must be 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Note: The Write Buffer Full Ratio and the Read Buffer Empty Ratio in the Device Configuration Page have the same function as the Motion Threshold in the Vendor Unique Parameters Page 1. If both pages are sent, the value that is received last by the CTS takes precedence. For more information about the motion threshold, see Section 3.6.
10 MODE SELECT (15h) and MODE SENSE (1Ah) If the RSmk bit is 1 and the EXB-8505 encounters a setmark, it returns Check Condition status with the sense key set to No Sense (0h). The ASC and ASQ fields will be set to 00h and 03h. Note: EXB-8205 If the tape format does not support setmarks (8500, 8200c, and 8200 formats), this bit is ignored in the MODE SELECT data. However, the EXB-8505 can return 1 for the RSmk bit in the MODE SENSE data, even if the tape format does not support setmarks.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 10, Bit 4 - EEG (Enable EOD Generation) The EEG bit indicates that the CTS will generate an EOD mark. The EEG bit is set to 1 in the MODE SENSE data and is ignored by the CTS in the MODE SELECT command. Byte 10, Bit 3 - SEW (Synchronize at Early Warning) The SEW bit indicates that the CTS will cause any buffered data to be written to the tape when the early-warning condition (LEOT) is detected during a write operation.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.13 Medium Partition Page (Page Code=11h) The Medium Partition Page enables you to format a tape containing one or two partitions (see Section 3.7 for information about partitions). Important The Medium Partition Page is available for the EXB-8505 writing in 8500c format only. If you send this page to an EXB-8205 or to an EXB-8505 that is not set to write in 8500c format, the CTS returns Check Condition status with the sense key set to Illegal Request (5h).
10 MODE SELECT (15h) and MODE SENSE (1Ah) When you format a partitioned tape, keep the following rules in mind: Before formatting new partitions, you must position the tape at LBOT (if it is currently a single-partition tape), or at the logical beginning of one of the partitions (if it is a dual-partition tape). The EXB-8505 must be set to write in 8500c format.
10 MODE SELECT (15h) and MODE SENSE (1Ah) For the long form, specify either 00h or 01h. Specify 00h to define no additional partitions (that is, the tape will have only one partition). Specify 01h to define one additional partition (the tape will have two partitions). Notes: If you are using the long form and specify 00h for Additional Partitions Defined, the CTS ignores bytes 08 and 09 of the Medium Partition Page (Partition Size field).
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 04, Bit 5 - IDP (Initiator Defined Partitions) The IDP bit tells the EXB-8505 to format the first partition on the tape based on the size provided in the Partition Size field (bytes 08 and 09). The values for IDP are as follows: 0 – Do not format the tape. (A value of 0 is always returned in the MODE SENSE data.) 1 – Format the tape with two partitions, as long the value in the Partition Size field (bytes 08 and 09) is not 0.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Table 10-11 Results of combinations of the FDP, SDP, and IDP bits in the Medium Partition Page (MODE SELECT) For these combinations... FDP SDP IDP 0 0 0 0 0 1 These results occur... When you specify no additional partitions (Additional Partitions Defined = 00h)... When you specify one additional partition (Additional Partitions Defined = 01h)... The EXB-8505 does not format the tape.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 04, Bits 4 and 3 - PSUM (Partition Size Unit of Measure) If you set IDP (Initiator Defined Partitions) to 1 and are defining additional partitions (Additional Partitions Defined = 01h), use the PSUM field to indicate the units you are using to specify the size of the additional partition. The valid values for PSUM are as follows: 00b – The partition size is specified in bytes. 01b – The partition size is specified in KBytes.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Bytes 08 and 09 - Partition Size The Partition Size field specifies the size of the first partition on the tape when IDP = 1 and Additional Partitions Defined is 01h. The partition size represents the amount of data space that will be available between the logical beginning of the partition (LBOP) and the logical end of the partition (LEOP). The size of the second partition is the remainder of the tape.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.14 Vendor Unique Parameters Page 1 (Page Code=20h) Bit Byte 00 7 6 5 03 3 Reserved 2 1 0 PE NAL RSVD 112m Page Code 01 02 4 Page Length CT RSVD ND RSVD RTF NBE WTF 04 Motion Threshold 05 Gap Threshold EBD Byte 00, Bits 5 through 0 - Page Code The Page Code identifies the page being transferred. The valid value is 20h (Vendor Unique Parameters Page 1).
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02, Bit 5 - ND This bit indicates whether the CTS can disconnect from the initiator during the data transfer phase, as follows: 0 – The CTS can disconnect during the data transfer phase. (Power-on default.) 1 – The CTS will not disconnect during the data transfer phase.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 02, Bit 2 - EBD (Even Byte Disconnect) This bit is used to enable disconnects on even-byte boundaries, as follows: 0 – Disconnect on any byte. 1 – Disconnect on even-byte (two-byte or four-byte) boundaries. Notes: An EEPROM option allows you to control what happens when the EBD bit is set to 1.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 03, Bits 7 through 5 - RTF (Read Tape Format) These bits are ignored by the CTS in the MODE SELECT command.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Byte 03, Bit 0 - 112m The 112m bit works in conjunction with the CT bit (byte 02, bit 7) to indicate the size of the data cartridge that is expected to be loaded in the CTS. Refer to Table 10-10 on page 10-21 for the combinations of settings for the CT and 112m bits. Notes: If you are using 160m XL data cartridges with an EXB-8505XL or EXB-8205XL, the CTS ignores the settings of the CT and 112m bits.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.15 Vendor Unique Parameters Page 2 (Page Code=21h) Bit Byte 00 7 6 5 4 3 Reserved 2 1 0 LPART WWR Page Code 01 Page Length 02 Reserved 03 Reserved 04 Reserved 05 Byte 00, Bits 5 through 0 - Page Code The Page Code identifies the page being transferred. The valid value is 21h (Vendor Unique Parameters Page 2). Byte 01 - Page Length The Page Length indicates the number of bytes in the Vendor Unique Parameters Page 2 that follow this byte.
10 MODE SELECT (15h) and MODE SENSE (1Ah) The EXB-8505 ignores this bit if you load a single-partition tape after issuing this command. EXB-8205 The EXB-8205 does not support partitioned tapes. The value for this bit must be 0. Byte 03, Bit 0 - WWR (Write Without Retries) This bit is ignored by the CTS in the MODE SELECT command. It is returned in the MODE SENSE data to indicate whether the tape was written with retries, as follows: 0 – Tape was written with retries. 1 – Tape was written with no retries.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.16 Data Compression Status Page (Page Code=22h) The Data Compression Status Page is available as MODE SENSE data only. You can use the information returned on this page to determine the CTS’s compression ratio. The Data Compression Status Page applies only when the CTS is writing in a compressed data format (8500c or 8200c for the EXB-8505; 8200c for the EXB-8205).
10 MODE SELECT (15h) and MODE SENSE (1Ah) Bytes 03 through 07 - Total Bytes Received The value returned for the Total Bytes Received field is a cumulative count of all data bytes received from the SCSI bus since one of the following events occurred: The CTS was reset (by a power-on, device, or SCSI bus reset) A change in the direction of tape motion occurred The data cartridge was unloaded The operating mode was changed from write to read Note: If no data bytes have been received, the value returned for
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.17 Exceptions and Error Conditions The following exceptions and error conditions can occur with the MODE SELECT command. Illegal Value in MODE SELECT Data If one of the bytes sent with the MODE SELECT data contains an illegal value or if a reserved bit is set, the CTS returns Check Condition status. To determine which byte contains the error, issue a REQUEST SENSE command.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 10.18 Tape Format Examples This section provides examples for using the CTS to write, append to, and read tapes in the following formats: 8500c format (EXB-8505) 8500 format (EXB-8505) 8200c format 8200 format As you review and use the examples in this section, keep the following rules in mind: The CTS allows only one format on any one tape. If you are writing data, you must decide on the tape’s format at LBOT.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Writing and Reading in 8500c Format (EXB-8505) This section describes how to use the EXB-8505 to write, append to, and read tapes in 8500c format. Writing 8500c Format Tapes The procedure you follow for writing in 8500c format depends on whether your SCSI driver supports MODE SELECT pages. (Refer to page 10-68 if you cannot issue MODE SELECT commands.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Appending to 8500c Format Tapes If a tape has already been written in 8500c format and you want to write additional data on the tape, follow these steps: 1. Load the data cartridge in the EXB-8505. Note: 2. Issue a READ (08h), SPACE (11h), or LOCATE (2Bh) command to move away from LBOT and to a legal position for appending. Note: 3. If you issue a MODE SELECT command at LBOT, be sure that the Density Code in the Block Descriptor is set to 8Ch.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Writing and Reading in 8500 Format (EXB-8505) This section describes how to use the EXB-8505 to write, append to, and read tapes in 8500 format. Writing 8500 Format Tapes To write tapes in 8500 format, follow these steps: 1. Load a blank data cartridge in the EXB-8505 (or load a previously written data cartridge that you want to overwrite). 2. Issue a MODE SELECT command at LBOT. Set the Density Code in the Block Descriptor to 15h. Note: 3.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Reading 8500 Format Tapes To use the EXB-8505 to read an 8500 format tape, follow these steps: 1. Load the data cartridge in the EXB-8505. 2. Issue a READ command to read the data. The EXB-8505 automatically determines the tape’s format. Writing and Reading in 8200c Format (EXB-8505 or EXB-8205) This section describes how to use the CTS to write, append to, and read tapes in 8200c format.
10 MODE SELECT (15h) and MODE SENSE (1Ah) 3. Issue a WRITE or WRITE FILEMARKS command to write the additional data. The CTS automatically sets the Density Code to 8200c format. Note: The WTF bit in the MODE SENSE data indicates that the CTS is writing in 8200c format (011b). Reading 8200c Format Tapes To use the CTS to read an 8200c format tape, follow these steps: 1. Load the data cartridge in the CTS. 2. Issue a READ command to read the data. The CTS automatically determines the tape’s format.
10 MODE SELECT (15h) and MODE SENSE (1Ah) Appending to 8200 Format Tapes If a tape has already been written in 8200 format and you want to write additional data on the tape, follow these steps: 1. Load the data cartridge in the CTS. 2. Issue a READ (08h) or SPACE (11h) command to move away from LBOT and to a legal position for appending. Note: 3. Legal positions for appending in 8200 format are the end of data (blank tape) or at the beginning of a long filemark.
10 MODE SELECT (15h) and MODE SENSE (1Ah) If You Cannot Issue MODE SELECT Commands If you cannot issue MODE SELECT commands to set the Density Code, follow these steps to write tapes in different formats: 1. Obtain a tape that has already been written in the desired format. This tape must include an LBOT pattern plus data or at least one filemark (or setmark in 8500c format). 2. Load the previously written tape in the CTS. 3. Issue a SPACE or READ command to move the tape away from LBOT.
11 PREVENT/ALLOW MEDIUM REMOVAL (1Eh) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 1 1 1 0 01 Logical Unit Number Reserved 02 Reserved 03 04 05 May 1994 Prevent Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 11-1
11 PREVENT/ALLOW MEDIUM REMOVAL (1Eh) 11.1 About This Command You can use the PREVENT/ALLOW MEDIUM REMOVAL command to allow or disallow the removal of the data cartridge from the CTS. Note: The PREVENT/ALLOW MEDIUM REMOVAL command is reservation independent. The CTS will execute a PREVENT/ALLOW MEDIUM REMOVAL command issued by any initiator even if the CTS is reserved by another initiator.
11 PREVENT/ALLOW MEDIUM REMOVAL (1Eh) 11.
11 PREVENT/ALLOW MEDIUM REMOVAL (1Eh) Notes: 11-4 EXB-8205 and EXB-8505 (Standard and XL) 510503
12 READ (08h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 0 1 0 0 0 01 Logical Unit Number SILI Fixed 02 Reserved (MSB) Transfer Length 03 04 05 May 1994 (LSB) Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 12-1
12 READ (08h) 12.1 About This Command The READ command transfers one or more bytes or blocks of data from the CTS to the initiator, beginning with the next logical block. Notes: For a read operation, the CTS automatically sets itself to the data format used when the tape was written. The CTS can read tapes that have a combination of fixed-length and variable-length data blocks.
12 READ (08h) Byte 01, Bit 0 - Fixed The Fixed bit defines the type of read operation being performed, as follows: 0 – A single logical block is read, and the length of this block is specified in the Transfer Length field. 1 – One or more fixed-length logical blocks are read, and the number of blocks is specified in the Transfer Length field.
12 READ (08h) 12.3 Exceptions and Error Conditions The following exceptions and error conditions can occur with the READ command. Filemark Detected If the CTS detects a filemark before completing the read operation, it returns Check Condition status.
12 READ (08h) Setmark Detected (EXB-8505 Only) Note: This error applies to tapes written in 8500c format only. If the RSmk bit in the MODE SELECT Device Configuration page (Page Code=10h) is set to 1 and the EXB-8505 detects a setmark before completing the read operation, the EXB-8505 returns Check Condition status.
12 READ (08h) EOD Detected If the CTS detects the EOD mark (or blank tape for 8200 format) during the read operation, it returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 1 Sense Key Blank Check (8h) Information bytes Depend on the setting of the Fixed bit, as follows: ■ If the Fixed bit is 0, equal the requested transfer length ■ If the Fixed bit is 1, equal the difference between the requested transfer length and the actual number of logical blocks read.
12 READ (08h) PEOT or PEOP Encountered During a read operation, if the CTS encounters the physical end of tape (PEOT) or the physical end of partition (PEOP) for 8500c format only, it returns Check Condition status.
12 READ (08h) Unrecoverable Error If an unrecoverable media or hardware error occurs during the read operation, the CTS terminates the READ command and returns Check Condition status.
12 READ (08h) Transfer Length Incorrect If the actual transfer length does not match the requested transfer length, the information reported depends on the setting of the Fixed bit. Variable Length Mode (Fixed = 0) If the Fixed bit is 0 and the actual length of the block on the tape does not match the transfer length requested, the CTS transfers the number of bytes available up to the transfer length requested.
12 READ (08h) Fixed Length Mode (Fixed = 1) If the Fixed bit is 1 and the actual length of any one block does not match the requested block length, the CTS transfers the number of blocks requested until it encounters the block with the incorrect length. Then, it terminates the READ command and returns Check Condition status.
12 READ (08h) Compression Errors The CTS can report two types of compression errors during a read operation: If the compression circuit is unable to decompress previously compressed data during a read operation, the CTS returns Check Condition status. The REQUEST SENSE data is set as follows: Sense Key Hardware Error (4h) ASC 11h ASCQ 00h FSC 18h If the read decompression CRC fails during a read operation, the CTS returns Check Condition status.
12 READ (08h) Notes: 12-12 EXB-8205 and EXB-8505 (Standard and XL) 510503
13 READ BLOCK LIMITS (05h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 0 0 1 0 1 01 Logical Unit Number 0 0 Reserved 02 Reserved 03 04 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 13-1
13 READ BLOCK LIMITS (05h) 13.1 About This Command The READ BLOCK LIMITS command requests that the CTS return data identifying the maximum and minimum logical block lengths supported. The data returned by the READ BLOCK LIMITS command applies to both the variable and fixed block lengths for the READ and WRITE commands. 13.2 Field Definitions Byte 05, Bits 7 and 6 - Vendor Unique There are no vendor unique definitions for this command. 13.
14 READ BUFFER (3Ch) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 1 1 1 1 0 0 01 Logical Unit Number 02 03 Reserved Mode Buffer ID (MSB) Buffer Offset 04 05 06 (LSB) (MSB) Allocation Length 07 08 09 May 1994 (LSB) Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 14-1
14 READ BUFFER (3Ch) 14.1 About This Command The READ BUFFER command is used to copy the CTS’s microcode across the SCSI bus to the initiator. This command is used with the WRITE BUFFER (3Bh) command to copy the microcode from one CTS to another CTS. Note: The READ BUFFER command does not transfer the CTS’s EEPROM image (see Appendix A) or MODE SELECT defaults to the initiator. To copy microcode from one CTS to another CTS, follow these steps: 1.
14 READ BUFFER (3Ch) 14.3 Exceptions and Error Conditions The following exceptions and error conditions can occur with the READ BUFFER command. Hardware or SCSI Bus Error If a hardware or SCSI bus error occurs while the microcode is being transferred from the CTS to the initiator, the CTS terminates the command and returns Check Condition status. The sense key is set to Aborted Command (Bh). If this occurs, retry the operation.
14 READ BUFFER (3Ch) Notes: 14-4 EXB-8205 and EXB-8505 (Standard and XL) 510503
15 READ POSITION (34h) 7 6 5 4 3 2 1 0 00 0 0 1 1 0 1 0 0 01 Logical Unit Number Bit Byte Reserved BT … 02 Reserved 08 09 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 15-1
15 READ POSITION (34h) 15.1 About This Command The READ POSITION command reports the CTS’s current logical position but does not cause tape motion to occur. As described in Chapter 7, the READ POSITION command is intended to be used with the LOCATE (2Bh) command to enable you to position the tape at a specified logical block address. Notes: The READ POSITION command is not supported for tapes written in 8200 format and will result in Check Condition status with the sense key set to Illegal Request (5h).
15 READ POSITION (34h) 15.
15 READ POSITION (34h) Byte 00, Bit 6 - EOP (End of Partition) The EOP bit indicates whether the tape is positioned at the end of a partition, as follows: 0 – The tape is not positioned at the end of a partition. 1 – For a dual-partition tape (8500c format only), the tape is positioned between the logical end of partition (LEOP) and the physical end of partition (PEOP) of the currently active partition.
15 READ POSITION (34h) Bytes 04 through 07 - First Block Location The First Block Location field indicates the block address associated with the current logical block position (that is, the block address of the next data block to be transferred between the initiator and the CTS if a READ or WRITE command is issued). When using a LOCATE command to search for this position, specify the value returned for this field as the Block Address in bytes 03 through 06 of the LOCATE CDB.
15 READ POSITION (34h) Notes: 15-6 EXB-8205 and EXB-8505 (Standard and XL) 510503
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 1 1 0 0 01 Logical Unit Number 02 03 Reserved Reserved (MSB) Allocation Length 04 05 May 1994 (LSB) TD VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 16-1
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) 16.1 About This Command You can use the RECEIVE DIAGNOSTIC RESULTS command for any of the following purposes: Obtaining the results of the tests requested by a previous SEND DIAGNOSTIC (1Dh) command. Obtaining a full or partial dump of the CTS’s memory. Obtaining a trace of SCSI and servo command activity for the CTS.
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) 16.2 Field Definitions Bytes 03 and 04 - Allocation Length The Allocation Length field specifies the number of bytes that the initiator has allocated for the return of RECEIVE DIAGNOSTICS RESULTS data. If you are using the command to obtain diagnostic data, the number of bytes of diagnostic data available from the CTS depends on the type of SEND DIAGNOSTIC test that was performed (see Section 16.3 for more information).
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) 16.3 Returning SEND DIAGNOSTIC Data When the initiator issues a RECEIVE DIAGNOSTIC RESULTS command with the TD bit set to 0, the CTS returns a diagnostic page. This page reports the results of the previous SEND DIAGNOSTIC command. Three types of diagnostic pages can be returned; the type of page depends on which diagnostic test was performed by the SEND DIAGNOSTIC command. As described in Section 16.
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) Bytes 02 and 03 - Page Length The Page Length field indicates the number Diagnostic Parameter bytes that follow this field. Table 16-2 indicates the Page Length values for each Page Code supported by the RECEIVE DIAGNOSTIC RESULTS command.
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) 16.4 Receiving a Processor Memory Dump This section describes the steps and bit settings for receiving complete and partial processor memory dumps. Table 16-4 shows the information available in the memory dump.
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) 16.5 Receiving a Trace Dump This section describes the steps and bit settings for receiving a trace dump. Trace dumps are used for detailed fault analysis and include a history of SCSI and servo command activity for the CTS. To receive a trace dump, follow these steps: 1. Issue a SEND DIAGNOSTIC command with the SelfTest, DevOfl, and UntOfl bits set to 0 and the MD bit set to 1. The Parameter List Length field is ignored and can have any value. 2.
16 RECEIVE DIAGNOSTIC RESULTS (1Ch) Format of SCSI Instruction Trace Table As shown in Figure 16-1, the first 256 bytes of the trace dump include information about SCSI commands that have been issued to the CTS.
17 RELEASE UNIT (17h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 1 1 1 01 Logical Unit Number 3rdPty Third Party Dev ID RSVD 02 Reserved 03 04 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 17-1
17 RELEASE UNIT (17h) 17.1 About This Command The RELEASE UNIT command releases a CTS from an initiator’s exclusive use or, if third-party reservations are in effect, from another SCSI device’s use. To have effect, the command must be issued by the initiator that reserved the CTS with a RESERVE UNIT (16h) command. It is not an error to attempt to release a CTS that is not currently reserved by the current initiator, but if the CTS is reserved by another initiator, then that reservation remains in effect.
18 REQUEST SENSE (03h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 0 0 0 1 1 01 Logical Unit Number 0 0 02 Reserved Reserved 03 04 05 May 1994 Allocation Length CLRCNT VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 18-1
18 REQUEST SENSE (03h) 18.1 About This Command The REQUEST SENSE command requests that the CTS transfer sense data to the initiator. The CTS returns a total of 29 (1Dh) bytes of sense data to the initiator. The sense data is valid for the Check Condition status just presented to the initiator. This sense data is preserved in the CTS for the initiator receiving the Check Condition status.
18 REQUEST SENSE (03h) 18.
18 REQUEST SENSE (03h) Byte 00, Bit 7 - Valid This bit is set to 1 when the data in the Information bytes (bytes 03 through 06) is valid for the command receiving the Check Condition status. The value of the Information bytes is undefined when this bit is 0. Byte 00, Bits 6 through 0 - Error Code A value of 70h for the Error Code field indicates that the sense data is associated with the command that received the Check Condition status.
18 REQUEST SENSE (03h) Table 18-1 Sense Key values Sense Key Meaning Explanation 0h No Sense Indicates that there is no specific sense key information to be reported for the designated logical unit. This occurs when a command completes successfully or returns Check Condition status with the FMK, EOM, or ILI bits set to 1. 1h Recovered Error Indicates that the last command completed successfully with some recovery action performed by the CTS.
18 REQUEST SENSE (03h) Sense Key Meaning 8h Blank Check 9h Exabyte Ah Copy Aborted Bh Aborted Command Explanation Indicates that EOD (blank tape) was encountered during a read, space, or locate operation. This is a vendor unique sense key used by Exabyte to indicate that a positioning error has occurred. The actual position of the CTS is undetermined and is not the expected position. This sense condition is not supported by the CTS. Indicates that the CTS aborted the command.
18 REQUEST SENSE (03h) Byte 09 - Log Parameter Code When a log parameter (write or read error counter) meets the threshold criteria specified with the TMC bit in the LOG SELECT command, the CTS sets this byte to the Parameter Code for the parameter. For more information about the LOG SELECT command, refer to Chapter 8. Byte 10 - Reserved This byte is reserved. Byte 11 - Underrun/Overrun Counter The Underrun/Overrun Counter is a dual-function counter for logging write underruns and read overruns.
18 REQUEST SENSE (03h) Byte 13 - Additional Sense Code Qualifier (ASCQ) The Additional Sense Code Qualifier, in conjunction with the Additional Sense Code (byte 12), provides additional information about each sense key. Appendix E lists the possible combinations of this byte and the ASC byte for each sense key. Only those ASCQ values used by the CTS are shown in the appendix. Bytes 14 and 15 - Reserved These bytes are reserved.
18 REQUEST SENSE (03h) Bytes 19 through 21 - Unit Sense For each status bit defined in the Unit Sense bytes, the normal or Good status is 0. When set to 1, these bytes indicate the condition defined for that bit, as follows. Note that the effective value for the RSVD bits is 0. Byte 19, Bit 7 - PF (Power Fail) The CTS has been reset since the last status, or the CTS has performed an internal reset due to power-up. Byte 19, Bit 6 - BPE (SCSI Bus Parity Error) The CTS detected a SCSI bus parity error.
18 REQUEST SENSE (03h) Byte 20, Bits 5 - WP (Write Protect) The data cartridge is write protected. Byte 20, Bit 4 - FMKE (Filemark Error) A write error occurred when the CTS was attempting to write a filemark. Byte 20, Bit 3 - URE (Under Run Error) A hardware data formatter underrun error occurred. (Byte 20, bit 0, is also set to 1.) Byte 20, Bit 2 - WE1 (Write Error 1) The maximum number of rewrites was attempted. Media error.
18 REQUEST SENSE (03h) Byte 22 - Reserved This byte is reserved. Bytes 23 through 25 - Remaining Tape The Remaining Tape field indicates the amount of tape remaining in 1,024-byte physical blocks. This is the LEOT position minus the current physical position. If the position is past the LEOT, the value is negative, indicating the number of physical blocks past LEOT. If there is no data cartridge loaded, the value is 0.
18 REQUEST SENSE (03h) Byte 28 - Fault Symptom Code The Fault Symptom Code (FSC) field is an Exabyte-unique byte used to indicate the specific nature of hardware and software errors or other events. Appendix E lists the errors indicated by the Fault Symptom Code byte. Note: The Fault Symptom Code field can also be used to determine the location of errors in the data sent with LOG SELECT (4Ch) and MODE SELECT (15h) commands.
19 RESERVE UNIT (16h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 1 1 0 01 Logical Unit No 3rdPty Third Party Dev ID RSVD 02 Reserved 03 04 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 19-1
19 RESERVE UNIT (16h) 19.1 About This Command The RESERVE UNIT command reserves the CTS for an initiator’s exclusive use or, if third-party reservations are in effect, for another SCSI device’s use. The reservation remains in effect until a RELEASE UNIT (17h) command is received from the same initiator or until the CTS is reset by a SCSI bus reset, a Bus Device Reset message, or a power-on reset. It is not an error for the initiator that made the last reservation to send another valid RESERVE UNIT command.
20 REWIND (01h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 0 0 0 0 1 01 Logical Unit Number Reserved Immed 02 Reserved 03 04 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 20-1
20 REWIND (01h) 20.1 About This Command The REWIND command causes the CTS to rewind the tape to the logical beginning of tape (LBOT) or, if the tape is formatted with two partitions (8500c format only), to the logical beginning of the partition (LBOP) in which the tape is currently positioned. (See Section 3.7 on page 3-23 for information about formatting and using partitioned tapes.) Notes: If the disconnect option is enabled, the CTS disconnects from the initiator while the REWIND command is executing.
20 REWIND (01h) 20.2 Field Definitions Byte 01, Bit 0 - Immed The Immed bit is used to determine when command status is returned to the initiator, as follows: 0 – Status is reported to the initiator when the REWIND command is completed. 1 – Status is reported to the initiator when the REWIND command is initiated by the CTS.
20 REWIND (01h) Notes: 20-4 EXB-8205 and EXB-8505 (Standard and XL) 510503
21 SEND DIAGNOSTIC (1Dh) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 1 1 0 1 01 Logical Unit Number PF RSVD SelfTest DevOfL UntOfL 02 03 Reserved (MSB) Parameter List Length 04 05 May 1994 (LSB) MD VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 21-1
21 SEND DIAGNOSTIC (1Dh) 21.1 About This Command The SEND DIAGNOSTIC command causes the CTS to perform certain self-diagnostic tests. If a test is successful, the CTS returns Good status; otherwise, it returns Check Condition status. When this command is followed by a RECEIVE DIAGNOSTIC RESULTS (1Ch) command or a REQUEST SENSE (03h) command, detailed results of these diagnostic tests are reported to the initiator.
21 SEND DIAGNOSTIC (1Dh) 21.2 Field Definitions Byte 01, Bit 4 - PF (Page Format) The Page Format bit specifies the format of the parameter list for the SEND DIAGNOSTIC command. The CTS does not support any pages, so the valid value for this field is 0. Byte 01, Bits 2 through 0 - SelfTest, DevOfL, UntOfL The SelfTest, DevOfL (Device Offline), and UntOfL (Unit Offline) bits are used together to determine the test to be performed and the data to be returned to the initiator.
21 SEND DIAGNOSTIC (1Dh) 21.3 Diagnostic Tests Table 21-1 lists the valid combinations of the SelfTest, DevOfL, UntOfL, Parameter List Length, and MD fields in the SEND DIAGNOSTIC command and the resulting actions performed by the CTS. Note that all other combinations of settings for these fields are undefined and will result in Check Condition status with the sense key set to Illegal Request.
21 SEND DIAGNOSTIC (1Dh) 21.4 Test Descriptions This section describes the memory dump and each type of diagnostic test. Processor Memory Dump The memory dump returns the current information from specified locations in the CTS’s processor memory. To perform a memory dump, set the SelfTest, DevOfL, and UntOfL bits to 000 and the MD bit to 1. Specify the starting address for the dump in the Parameter List Length field. Then, immediately issue a RECEIVE DIAGNOSTIC RESULTS command.
21 SEND DIAGNOSTIC (1Dh) Test 100 (Power-on Tests without Tape) During this test, the CTS performs its power-on RAM and servo diagnostic tests. The CTS returns Good status if it finds no errors. Incorrect test setup causes the CTS to return Check Condition status with the sense key set to Illegal Request. The CTS disconnects during this test. Note: Test 100 erases the trace tables. In addition, the unload button is disabled during this test.
21 SEND DIAGNOSTIC (1Dh) Note: Test 101 erases the trace tables. In addition, the unload button is disabled during this test. Setup for Test 101 Before starting this test, power the CTS on but do not insert a data cartridge. Issue a TEST UNIT READY (00h) command. The CTS must return Check Condition status. Then, issue a REQUEST SENSE command. The sense key must be set to Not Ready (no data cartridge present).
21 SEND DIAGNOSTIC (1Dh) Test 111 (Power-on, Write/Read, and Load Tests with Tape—Tape Preloaded at Start of Test) During this test, the CTS first performs its power-on RAM and servo diagnostic tests.
22 SPACE (11h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 0 0 1 01 Logical Unit Number 02 Reserved Code (MSB) Count 03 04 05 May 1994 (LSB) ADE VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 22-1
22 SPACE (11h) 22.1 About This Command The SPACE command enables the CTS to perform forward or backward searches. You can use this command to space directly to the end of data or to space over a specified number of logical blocks, filemarks, or setmarks (8500c format only). Notes: The CTS can space over both fixed- and variable-length logical blocks; it determines the type of spacing to use according to the type of block found on the tape.
22 SPACE (11h) 22.2 Field Definitions Byte 01, Bits 2 through 0 - Code As shown in Table 22-1, the Code field specifies the type of space operation you want the CTS to perform. Table 22-1 Values of Code field for the SPACE command Value of Code field Type of operation 000b Space over n fixed or variable-length blocks See Section 22.3 for information about the errors and exceptions that can occur for this setting. 001b Space over n filemarks See Section 22.
22 SPACE (11h) Bytes 02 through 04 - Count The Count field represents the number of blocks, filemarks, or setmarks (8500c format only) to be spaced over. The value of n determines the direction of spacing, as follows: A positive value of n in the Count field causes the CTS to space forward n blocks, filemarks, or setmarks. When the space operation is complete, the tape is logically positioned on the EOT side of the nth block, filemark, or setmark.
22 SPACE (11h) Byte 05, Bit 6 - Vendor Unique There is no vendor unique definition for this bit. 22.3 Exceptions and Error Conditions The following exceptions and error conditions can occur with the SPACE command. Filemark Detected If the Code field has a value of 000b (space over n logical blocks) and a filemark is detected, the CTS returns Check Condition status.
22 SPACE (11h) Setmark Detected (EXB-8505) Note: This error applies to tapes written in 8500c format only. If the Code field has a value of 000b (space over n logical blocks) or 001b (space over n filemarks) and a setmark is detected, the EXB-8505 looks at the setting of the RSmk bit on the MODE SELECT Device Configuration page (Page Code=10h): If the bit is 0 (do not report setmarks), the EXB-8505 continues to space over blocks or filemarks.
22 SPACE (11h) EOD (Blank Tape) Detected If the Code field has a value of 000b (space over n logical blocks), 001b (space over n filemarks), or 100b (space over n setmarks in 8500c format), and the EOD mark (or blank tape in 8200 format) is detected, the CTS returns Check Condition status.
22 SPACE (11h) PEOT or PEOP Encountered If the physical end of tape (PEOT) or physical end of partition (PEOP) for 8500c format is encountered during a space operation (regardless of the value of the Code field), the CTS returns Check Condition status.
22 SPACE (11h) PBOT or PBOP Encountered If the Code field has a value of 000b, 001b, or 100b (space over logical blocks, filemarks, or setmarks) and the physical beginning of tape (PBOT) or physical beginning of partition (PBOP) for 8500c format is encountered, the CTS returns Check Condition status.
22 SPACE (11h) Unrecoverable Error If an unrecoverable media or hardware error occurs during the space operation, the CTS terminates the SPACE command and returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 0 or 1 Sense Key Medium Error (3h) or Hardware Error (4h) Information bytes If Valid=1, indicate the difference between the requested number of blocks, filemarks, or setmarks and the actual number of blocks, filemarks, or setmarks spaced over.
23 TEST UNIT READY (00h) 7 6 5 4 3 2 1 0 00 0 0 0 0 0 0 0 0 01 Logical Unit Number 0 0 Bit Byte Reserved 02 Reserved 03 04 05 May 1994 Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 23-1
23 TEST UNIT READY (00h) 23.1 About This Command The TEST UNIT READY command provides a means for determining if the CTS is ready to accept an appropriate medium access command. The TEST UNIT READY command returns Good status if the CTS is ready to accept a medium access command without returning Check Condition status. The TEST UNIT READY command returns Check Condition status with the sense key set to Not Ready (2h) if the CTS is not ready to accept a medium access command.
24 VERIFY (13h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 0 1 1 01 Logical Unit Number Immed BytCmp Fixed 02 Reserved (MSB) Verification Length 03 04 05 May 1994 (LSB) Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 24-1
24 VERIFY (13h) 24.1 About This Command The VERIFY command enables the CTS to verify one or more logical blocks of data on the tape, beginning with the next logical block. When the VERIFY command is completed, the tape is positioned on the EOT side of the last block of data verified. 24.2 Field Definitions Byte 01, Bit 2 - Immed The immediate bit determines when command status is returned to the initiator, as follows: 0 – Status is returned to the initiator when the verify operation is complete.
24 VERIFY (13h) Note: The CTS returns Check Condition status with the sense key set to Illegal Request (5h) if the Fixed field in the VERIFY command is 1 (fixed-length logical blocks) and the Block Length field in the current MODE SELECT data is 0 (variable-length logical block). The ASC and ASCQ bits are set to 81h and 00h (fixed/variable mismatch).
24 VERIFY (13h) 24.3 Exceptions and Error Conditions The following exceptions and error conditions can occur with the VERIFY command. Filemark Detected If a filemark is detected before the verify operation is completed, the CTS returns Check Condition status.
24 VERIFY (13h) Setmark Detected (EXB-8505 Only) Note: This error applies to tapes written in 8500c format only. If the RSmk bit in the MODE SELECT Device Configuration page (Page Code=10h) is set to 1 and the EXB-8505 detects a setmark before completing the verify operation, the EXB-8505 returns Check Condition status.
24 VERIFY (13h) EOD Detected If the CTS detects the EOD mark (or blank tape in 8200 format) during the verify operation, it returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 1 Sense Key Blank Check (8h) Information bytes Depend on the setting of the Fixed bit, as follows: ■ If the Fixed bit is 0, equal the requested verification length ■ If the Fixed bit is 1, equal the difference between the requested verification length and the actual number of logical blocks verified.
24 VERIFY (13h) Unrecoverable Error If an unrecoverable media or hardware error occurs during the verify operation, the CTS terminates the VERIFY command and returns Check Condition status.
24 VERIFY (13h) Verification Length Incorrect If the actual verification length does not match the requested verification length, the information reported depends on the setting of the Fixed bit. Variable Length Mode (Fixed = 0) If the Fixed bit is 0 and the actual length of the block on the tape does not match the verification length requested, the CTS verifies the number of bytes available up to the verification length requested. Then, it terminates the VERIFY command and returns Check Condition status.
24 VERIFY (13h) Fixed Length Mode (Fixed = 1) If the Fixed bit is 1 and the actual length of any one block does not match the requested block length, the CTS verifies the number of blocks requested until it encounters the block with the incorrect length. Then, it terminates the VERIFY command and returns Check Condition status.
24 VERIFY (13h) Notes: 24-10 EXB-8205 and EXB-8505 (Standard and XL) 510503
25 WRITE (0Ah) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 0 1 0 1 0 01 Logical Unit Number 02 Reserved Fixed (MSB) Transfer Length 03 04 05 May 1994 (LSB) Vendor Unique Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 25-1
25 WRITE (0Ah) 25.1 About This Command The WRITE command transfers one or more bytes or blocks of data from the initiator to the CTS. As described in Section 1.1, the EXB-8505 can write data in 8500c, 8500, 8200c, or 8200 format; the EXB-8205 can write data in 8200c or 8200 format. The data format is set with the MODE SELECT (15h) command. Only one data format can be written on a data cartridge.
25 WRITE (0Ah) Bytes 02 through 04 - Transfer Length The Transfer Length field defines the amount of data you want the CTS to write, as follows: When the Fixed bit is set to 0 (variable length), the Transfer Length field contains the length of the logical block in bytes. The logical block can be any size from 0 to 240 KBytes. When the Fixed bit is set to 1 (fixed length), the Transfer Length field contains the number of logical blocks to be written.
25 WRITE (0Ah) 25.3 Tape Positioning This section describes the legal tape positions for a write operation. Tape Positioned at LBOT or LBOP When writing to a tape positioned at LBOT or LBOP (8500c format only), the CTS automatically writes a new LBOT (or LBOP) pattern and then writes the data from the buffer. The data is written in the power-on default density or in the density specified with the currently active MODE SELECT command.
25 WRITE (0Ah) 25.4 Data Buffering The CTS provides two modes of operation for the WRITE command: unbuffered and buffered. The mode of operation is set with the MODE SELECT command (byte 02, bits 6 through 4, in the Parameter List Header). Unbuffered Write Operation When the CTS is set for an unbuffered write operation, it returns Good status as soon as all data blocks are written to tape.
25 WRITE (0Ah) 25.5 Exceptions and Error Conditions The following exceptions and error conditions can occur with the WRITE command. Write-Protected Data Cartridge If a write operation is attempted on a data cartridge that is write protected, the CTS returns Check Condition status with the sense key set to Data Protect (7h).
25 WRITE (0Ah) Table 25-2 Action if LEOT or LEOP is encountered during a WRITE command Setting of Fixed bit in current CDB Fixed=0 (variable-length logical block) The CTS returns Check Condition status after all data has been written to tape. The extended sense data is set as follows: LEOT or LEOP encountered during current write operation Error Code=70h EOM=1 Sense Key=0h (No Sense) LBOT=0 The CTS returns Check Condition status after all data has been written to tape.
25 WRITE (0Ah) Encountering LEOT or LEOP Because of a Previous WRITE Command To understand how LEOT or LEOP (8500c format only) can be encountered because of a previous WRITE command, consider the following hypothetical situation. Important If LEOT (or LEOP) is encountered as a result of a previous WRITE command, the CTS may write as much as 1 MByte of data (in compressed format) after LEOT (or LEOP) before reporting this condition. This represents the full contents of the buffer.
25 WRITE (0Ah) Example 1. The initiator issues five buffered WRITE commands to the CTS (WRITE 1 through WRITE 5). The 500 KBytes of data (assumed to be uncompressed) associated with these commands is transferred to the CTS’s buffer, but it does not cause tape motion to begin because the 512-KByte motion threshold has not been exceeded. After receiving the data for each command, the CTS returns Good status to the initiator, indicating that the command completed successfully. 2.
25 WRITE (0Ah) 5. 6. As the CTS writes the data associated with WRITE 2 to tape, it encounters LEOT. As a result, the next WRITE command (WRITE 9) terminates abnormally and receives Check Condition status.
25 WRITE (0Ah) PEOT or PEOP Encountered If the physical end of tape (PEOT) or physical end of partition (PEOP) for 8500c format is encountered, the CTS terminates the WRITE command and returns Check Condition status.
25 WRITE (0Ah) Compression Errors If you are writing in compressed format and the decompressed data does not match the compressed data during the Compression Integrity Check, the CTS aborts the data transfer. The data block containing the compression error is not written to tape. After aborting the data transfer, the CTS sends Check Condition status to the initiator, followed by a Command Complete message. The sense key is set to Aborted Command (Bh), and the ASC and ASCQ are set to 10h and 00h.
25 WRITE (0Ah) Illegal Requests The following conditions cause the CTS to return Check Condition status with the sense key set to Illegal Request (5h): The Fixed bit is set to 0 and the requested block length is greater than 240 KBytes. The Fixed bit is set to 1 and the block length in the MODE SELECT command is 0. The tape position is invalid. A READ (08h), SPACE (11h) in a forward direction, LOCATE (2Bh) in a forward direction, or VERIFY (13h) command is issued after the WRITE command is issued.
25 WRITE (0Ah) Notes: 25-14 EXB-8205 and EXB-8505 (Standard and XL) 510503
26 WRITE BUFFER (3Bh) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 1 1 1 0 1 1 01 Logical Unit Number 02 03 Reserved Mode Buffer ID (MSB) Buffer Offset 04 05 06 (LSB) (MSB) Parameter List Length 07 08 09 May 1994 (LSB) WBF VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 26-1
26 WRITE BUFFER (3Bh) 26.1 About This Command The WRITE BUFFER command allows you to load new microcode from the SCSI bus into the CTS’s control memories. This command is used with the READ BUFFER (3Ch) command to copy the microcode from one CTS to another CTS. Note: You may want to issue more than one WRITE BUFFER command if the initiator has less than 176 KBytes of buffer space available.
26 WRITE BUFFER (3Bh) Cautions for Using the WRITE BUFFER Command CAUTION Be sure to follow these cautions when issuing the WRITE BUFFER command: The WRITE BUFFER command allows you to load new microcode from the SCSI bus into the CTS. It is not intended to be used for testing CTS functionality (that is, do not issue this command unless you are actually loading new microcode). Do not load microcode from one model of CTS into another.
26 WRITE BUFFER (3Bh) 26.2 Field Definitions Byte 01, Bits 2 through 0 - Mode The Mode field determines the type of operation to be performed. The only operation supported by the CTS is loading and saving the microcode. The bits in this field must be set to 101b. Byte 02 - Buffer ID This field must be 0.
26 WRITE BUFFER (3Bh) Byte 09, Bit 7 - WBF (WRITE BUFFERs Follow) The WBF bit specifies whether the new microcode is being sent using one or more WRITE BUFFER commands, as follows: 0 – This is the only WRITE BUFFER command, or this is the last WRITE BUFFER command in a sequence. 1 – This is one of several (but not the last) WRITE BUFFER commands in a sequence.
26 WRITE BUFFER (3Bh) Fatal Load Error Once the load process is started, it is irreversible. If a hardware or power failure occurs during the load operation, the CTS may not be able to operate. In this event, you can use the CTS Monitor program to reload the microcode through the Monitor port (refer to the documentation for CTS Monitor ).
27 WRITE FILEMARKS (10h) Bit Byte 7 6 5 4 3 2 1 0 00 0 0 0 1 0 0 0 0 01 Logical Unit Number WSmk Immed 02 Reserved (MSB) Number of Filemarks 03 04 05 May 1994 (LSB) Short VU Reserved EXB-8205 and EXB-8505 (Standard and XL) 0 0 27-1
27 WRITE FILEMARKS (10h) 27.1 About This Command The WRITE FILEMARKS command causes the CTS to write one or more filemarks or setmarks (available in 8500c format only) to tape. In 8500c, 8500, and 8200c formats, filemarks can be buffered. Setmarks (8500c format only) can also be buffered. Each buffered filemark or setmark uses 1 KByte of the CTS’s 1-MByte buffer. In 8200 format, filemarks cannot be buffered.
27 WRITE FILEMARKS (10h) Byte 01, Bit 0 - Immed The Immediate bit determines when command status is returned to the initiator, as follows: 0 – Status is reported to the initiator when the WRITE FILEMARKS command is completed. All buffered data, filemarks, and setmarks (8500c format only) are written to the tape before the command is completed. 1 – Status is reported to the initiator when the WRITE FILEMARKS command is initiated by the CTS.
27 WRITE FILEMARKS (10h) 27.3 Tape Positioning This section describes the legal tape positions for a write filemarks operation. Tape Positioned at LBOT or LBOP When writing to a tape positioned at the logical beginning of tape (LBOT) or at the logical beginning of partition (LBOP) for 8500c format, the CTS automatically writes a new LBOT pattern and then writes the requested number of filemarks (or setmarks).
27 WRITE FILEMARKS (10h) 27.4 Exceptions and Error Conditions The following exceptions and error conditions can occur with the WRITE FILEMARKS command. Write-Protected Data Cartridge If a write filemarks operation is attempted on a data cartridge that is write protected, the CTS returns Check Condition status with the sense key set to Data Protect (7h).
27 WRITE FILEMARKS (10h) PEOT or PEOP Encountered If the physical end of tape (PEOT) or physical end of partition (PEOP) for 8500c format is encountered, the CTS terminates the WRITE FILEMARKS command and returns Check Condition status. The REQUEST SENSE data is set as follows: Valid 0 or 1 EOM 1 Information bytes If Valid=1, contain the difference between the requested number of filemarks (or setmarks) and the actual number of filemarks (or setmarks) written.
A EEPROM Options This appendix describes the CTS’s EEPROM options and describes how you can request these options when you order a CTS from Exabyte. As this appendix describes, EEPROM options include such items as MODE SELECT power-on default values, options for the data returned by the INQUIRY and REQUEST SENSE commands, command set options, and hardware and SCSI configuration options.
Appendix A EEPROM Options What are EEPROM Options? When the CTS is manufactured, many of its operating features and default values are programmed in electronically erasable programmable read-only memory (EEPROM). These operating features and default values are set according to a standard configuration that should meet the needs of most data back-up and storage situations.
Appendix A EEPROM Options How to Use This Appendix The tables in this appendix are grouped by EEPROM option function, as described below. A sample table on the next page shows the types of information included in the tables. Power-On Defaults These are SCSI command defaults that take effect each time you power-up the CTS. You can temporarily change these settings at any time during CTS operation by issuing the command. You can also change many of these settings using the CTS Monitor program.
Appendix A EEPROM Options Hardware Operation Options These are options that permanently determine how various CTS hardware features operate. You cannot change these options with any SCSI command. However, you can change some of them using the CTS Monitor program. Table A-7 starting on page A-20 describes options for customizing CTS hardware operations. SCSI Configuration Options These are options that control SCSI communication and data transfer operations.
Appendix A EEPROM Options EEPROM Options for MODE SELECT Defaults As shown in Table A-1, many EEPROM options allow you to specify the power-on defaults for various fields in the MODE SELECT command. These power-on defaults can be overridden by issuing a MODE SELECT command at any time during CTS operation. Note: The options in Table A-1 are arranged in MODE SELECT Page Code order. (For example, options for Page Code 01h are listed before options for Page Code 20h.
Appendix A EEPROM Options EEPROM option Definition Possible values Read retry count Read Retry Count – Byte 03 of the Read-Write Error Recovery Page—see page 10-26. Default value Option is set to... 00h – The CTS will not reread any physical blocks during a read operation. 01h – The CTS will reread a physical block one time before reporting an unrecoverable read error. 0Bh (defaults to two retries) 0Bh – The CTS will reread a physical block two times before reporting an unrecoverable read error.
Appendix A EEPROM Options EEPROM option Write delay time Definition Possible values Write Delay Time – Bytes 06 and 07 of the Device Configuration Page—see page 10-41. (EXB-8505 only) RSmk – Byte 08, bit 5, of the Device Configuration Page—see page 10-41. Note: This option applies only to 8500c format. It is ignored for other data formats. Report early REW (Report Early Warning) – Byte 08, bit 0, of the Device warning Configuration Page—see page 10-42. Option is set to...
Appendix A EEPROM Options EEPROM option No disconnect during data transfer Even byte disconnect Definition Possible values ND – Byte 02, bit 5, of the Vendor Unique Parameters Page 1—see page 10-52. DISCONNECTS ALLOWED – Disconnects are allowed during data transfers. ND – Byte 00, bit 5, of the Vendor Unique Parameters (non-page format)—see page 10-22. DISCONNECTS NOT ALLOWED – Disconnects are not allowed during data transfers.
Appendix A EEPROM Options EEPROM option Definition Possible values Gap threshold Gap Threshold – Byte 05 of the Vendor Unique Parameters Page 1—see page 10-55. Default value Option is set to... 0 to 7h Gap Threshold – Byte 02, Bits 2 through 0, of the Device Configuration Page—see page 10-39. 7h Gap Threshold – Byte 04 of the Vendor Unique Parameters (non-page format)—see page 10-24. Load to partition (EXB-8505 only) LPART – Byte 03, bit 1, of the Vendor Unique Parameters Page 2—see page 10-56.
Appendix A EEPROM Options EEPROM Options for INQUIRY Data As shown in Table A-3, several EEPROM options are available for controlling the data returned by the CTS in response to the INQUIRY (12h) command. You cannot override or change these options with the INQUIRY command. Note: For more information about the data returned by the INQUIRY command, refer to Chapter 5.
Appendix A EEPROM Options EEPROM Options for MODE SELECT / MODE SENSE As shown in Table A-4, several EEPROM options are available for controlling how the MODE SELECT (15h) and MODE SENSE (1Ah) commands operate. Unlike the MODE SELECT power-on default values listed in Table A-1, you cannot override or change these options with a MODE SELECT or MODE SENSE command. Note: For more information about the MODE SELECT and MODE SENSE commands, refer to Chapter 10.
Appendix A EEPROM Options EEPROM option Definition Ignore illegal density changes Controls the reporting of errors if you attempt to change the Density Code when the tape is not positioned at LBOT. This option controls whether an error is reported if the Density Code selected does not agree with the current tape format. (See page 10-17 for information about the Density Code.) NO – Report an error if an illegal density change is attempted and the tape is not at LBOT.
Appendix A EEPROM Options EEPROM option Definition Possible values Report Media Type in MODE SENSE Controls what is reported for the Medium Type byte in MODE SENSE (byte 01 of the Parameter List Header—see page 10-14). YES – The CTS should report a medium type code based on the cartridge type for the currently loaded tape. Default value Option is set to... YES NO – The CTS should report 00h for the Medium Type byte.
Appendix A EEPROM Options EEPROM option REQUEST SENSE format Definition Specifies the number of bytes of data returned by the REQUEST SENSE command. Possible values Controls what is reported for the TNP (Tape Not Present) and LBOT bits in byte 19 of the Request Sense data. Option is set to... EXB-8500 – The REQUEST SENSE command returns 29 bytes of data in the standard form. EXB-8200 – The REQUEST SENSE command returns 26 bytes of data. A deferred error code is never returned in byte 0.
Appendix A EEPROM Options EEPROM option Definition Possible values Set EOM at LEOT Controls what the CTS reports when it encounters LEOT during a read operation. YES – The CTS should set the EOM bit when it encounters LEOT during a read. (SCSI-2) Default value Option is set to... YES NO – The CTS should not set the EOM bit when it encounters LEOT during a read. Controls the reporting of Unit Attention on Unit Attention (FSC=C4h) button press when you press the unload button.
Appendix A EEPROM Options EEPROM option LOCATE command Definition Possible values Controls whether the CTS supports the LOCATE (2Bh) command. Default value Option is set to... LEGAL – The command is legal. ILLEGAL – The command is illegal. LEGAL See Chapter 7 for more information. PREVENT/ ALLOW MEDIUM REMOVAL command Controls whether the CTS supports the PREVENT/ALLOW MEDIUM REMOVAL (1Eh) command. LEGAL – The command is legal. ILLEGAL – The command is illegal.
Appendix A EEPROM Options EEPROM option RECEIVE DIAGNOSTIC RESULTS command Definition Possible values Controls how the RECEIVE DIAGNOSTIC RESULTS (1Ch) command operates. SCSI-2 – The RECEIVE DIAGNOSTIC RESULTS command is legal only after a SEND DIAGNOSTIC (1Dh) command. See Chapter 16 for more information. EXB-8200 – The RECEIVE DIAGNOSTIC RESULTS command can always be issued independently of a SEND DIAGNOSTIC command.
Appendix A EEPROM Options EEPROM option Definition Possible values SEND DIAGNOSTIC special operation Controls the reporting of an error if a tape is present in the CTS during Test 100 of the SEND DIAGNOSTIC (1Dh) command. Also enables you to convert the SEND DIAGNOSTIC command to a no-op. NORMAL – The SEND DIAGNOSTIC command works as determined by the SEND DIAGNOSTIC command option (see the previous option). If you select Test 100 and a tape is present, the test executes as if no tape were present.
Appendix A EEPROM Options EEPROM option Definition Possible values SPACE command Controls how the space-to-EOD operation of the SPACE (11h) command operates. SCSI-2 – Space-to-EOD operations are allowed. The Information bytes can be positive or negative. POSITIVE – Space-to-EOD operations are allowed. The Information bytes are always positive. See Chapter 22 for more information. Default value Option is set to... SCSI-2 EXB-8200 – Space-to-EOD operations are not allowed.
Appendix A EEPROM Options EEPROM option Immediate Write Filemark Definition Controls whether the CTS supports the Immed bit (byte 01, bit 0) in the WRITE FILEMARK (10h) command. Possible values Default value Option is set to... LEGAL – The Immed bit is legal. ILLEGAL – The Immed bit is illegal. LEGAL See Chapter 27 for more information.
Appendix A EEPROM Options EEPROM Options for Hardware Operations As shown in Table A-7, a number of EEPROM options allow you to customize CTS hardware operations. You cannot override or change these options with any command. Table A-7 EEPROM options for hardware operations EEPROM option Definition Possible values Button action Controls what happens when you press the unload button.
Appendix A EEPROM Options EEPROM option Autosize the tape Definition Possible values Controls how the CTS autosizes tapes. See Appendix C for more information. Monitor data compression mode See page 3-9 for more information. Option is set to... YES – The CTS should autosize the tape as tape motion proceeds. NO – The CTS should determine the tape size using its estimate at LBOT along with the values specified for the CT and 112m bits.
Appendix A EEPROM Options EEPROM Options for the SCSI Configuration As shown in Table A-8, a number of EEPROM options allow you to customize the CTS’s SCSI configuration. You cannot override or change these options with any command. Table A-8 EEPROM options for the SCSI configuration EEPROM option Synchronous negotiations Definition Possible values Controls the operation of Synchronous Data Transfer Request (01h) messages. See page 2-16 for more information. Default value Option is set to...
Appendix A EEPROM Options EEPROM option Maximum reselection tries Reselection timeout Definition Possible values Controls the maximum number of times that the CTS will attempt to reconnect to the initiator before giving up. Each reselection will time out after either 5 msec or 250 msec, depending on what you select for the Reselection timeout option (see the next option). 0 – The CTS should continue to reselect the initiator until it works. There is no limit on the number of attempts.
Appendix A EEPROM Options EEPROM option Definition Possible values Status/ Command Complete Controls whether the CTS drops the BSY line quickly (about 5 µsec after the Command Complete message) or whether the CTS waits longer to drop the BSY line to accommodate drivers that require the BSY line to be enabled for a longer period of time. Default value Option is set to... NORMAL – The CTS manually reconnects, sends status, and sends the Command Complete message to the initiator.
Appendix A EEPROM Options True Areal Density Selection EEPROM Option The True Areal Density Selection option enables you to choose how the Density Code and the Data Compression Page are used to specify the tape format and to enable data compression. Two options are available: EXB-8500 and SCSI-2. EXB-8500 Option (Density Code reflects logical tape format) The EXB-8500 option reflects the density selection implementation that is described in this manual.
Appendix A EEPROM Options EXB-8205 For the EXB-8205, the following Density Codes are available: 00h Default format 14h 8200 uncompressed format 7Fh No change in format 90h 8200c compressed format SCSI-2 Option (Density Code reflects the areal bit density) When you choose the SCSI-2 option, “density” is interpreted more strictly to mean the areal density of the bits on the tape.
Appendix A EEPROM Options Table A-9 lists the data formats resulting when you specify various combinations of Density Code and the DCE bit in MODE SELECT with the SCSI-2 option. Table A-9 Data formats resulting from combinations of Density Code and DCE bit (SCSI-2 option) Density Code 00ha 14h 15h 7Fha DCE bit Format of data written to tape... Equivalent Density Code (if you choose the EXB-8500 option)... ...by the EXB-8505 ...by the EXB-8205 ...for the EXB-8505 ...
Appendix A EEPROM Options Table A-10 Effect of True Areal Density Selection options on MODE SENSE data EXB-8500 Option If the tape format is... SCSI-2 Option Density Code returned as.. DCE returned as... Density Code returned as.. DCE returned as..
Appendix A EEPROM Options The following sections describe these options in more detail. WRITE Option (MODE SELECT sets the writing format) The WRITE option reflects the Density Code implementation that is described in the MODE SELECT chapter of this manual. When you choose the WRITE option, the CTS interprets the Density Code and the DCE bit in the MODE SELECT command to mean the “writing format at LBOT” for the CTS.
Appendix A EEPROM Options Table A-12 Summary of READ option for Legal Non-LBOT Density EEPROM option Is it legal? Does it change the default writing format? Does it change the current writing format? any density Y Y Y any compression format Y Y Y default writing format N* – – tape’s actual format Y N N other format N – – MODE Density Code and SELECT DCE bit set to... issued when...
Appendix A EEPROM Options Effect of the READ Option on DCE Bit in MODE SENSE Data The value returned for the DCE bit in MODE SENSE for the READ option depends on the type of MODE SENSE data being returned and the tape’s format, as shown in Table A-14. Table A-14 Value returned for the DCE bit in MODE SENSE for the READ option Actual tape format Type of MODE SENSE data returned...
Appendix A EEPROM Options In contrast, suppose you attempt to change the Density Code to 14h after completing step 3. The EXB-8505 returns Check Condition status with the sense key set to Illegal Request (5h), indicating that you can’t change the Density Code when the tape is not at LBOT. (This is because you can only have one data density on a tape.) Again, this result is what you would expect and it does not depend on the EEPROM option.
B Directory Support The CTS’s directory support feature provides a method of maintaining a directory on a tape when partition support is not available. You can use this directory to find out what data is on the tape and to locate that data quickly and efficiently. The directory support feature is available as an EEPROM option (see the “Allow position past EOD” option on page A-21). Directory support is not included in the standard CTS and is not supported for tapes written in 8200 format.
Appendix B Directory Support Overview of Directory Support The sample application in this appendix shows one method for creating a tape that uses the directory support feature. This sample uses the READ POSITION (34h) and LOCATE (2Bh) commands to implement directory support, but you can use the SPACE (11h) command as well. Figure B-1 shows how the information will be arranged on a tape that was created using this method. LBOT MASTER DIR EOD1 PAD LFM DS 1 DIR1 . . .
Appendix B Directory Support Sample Application for Directory Support The step-by-step description that follows explains how to create this data structure and access the data using the READ POSITION and LOCATE commands. Restrictions on Similar Applications The sample application in this appendix demonstrates only a suggested implementation of directory support.
Appendix B Directory Support Converting EXB-8200SX Drivers EXB-8200SX directory support drivers should work for EXB-8505 or EXB-8205 directory support with only a few modifications. These modifications include the following: Any filemarks in the directory must be removed. Directories must be less than 10 MBytes. If you are using 8500c format, remember to disable data compression when you write the pad areas to ensure that they are the correct length, as explained on page B-3.
Appendix B Directory Support Writing Data for Directory Support To write data to make use of the directory support feature and the READ POSITION and LOCATE commands, follow these steps: 1. At LBOT, create a directory pad by writing “filler” data (data that you do not intend to store) to tape. This reserves an area of tape for the master directory that will list the location of the data sets on tape. LBOT DIRECTORY PAD The directory pad can be up to 10 MBytes in length.
Appendix B Directory Support 2. Using additional uncompressed “filler” data, create a second pad after the directory pad. The minimum size for the second pad is 12 MBytes. This pad allows room for the erase head position and the EOD mark written when you rewind the tape after updating the master directory. Note: LBOT 3. DIRECTORY PAD 12 MBYTE PAD Write a long filemark after the 12-MByte pad. This filemark provides a clear separation between the pad and data areas. LBOT 4.
Appendix B Directory Support 5. Write the first data set (DS 1) to the tape. While the data set is being written, issue additional READ POSITION commands as desired to obtain the locations of individual files, blocks, and so on contained in the data set. Note: If you are writing data in 8500c format, remember to re-enable compression by setting the DCE bit to 1. Save the data returned for each READ POSITION command; it will be written later to the data set’s directory (DIR 1). 2.
Appendix B Directory Support B-8 EXB-8205 and EXB-8505 (Standard and XL) 510503
Appendix B Directory Support 7. LBOT Write the READ POSITION data obtained for the various files and blocks in the first data set (DS 1) to the first data set’s directory (DIR 1). DIRECTORY PAD 12 MBYTE PAD LFM DS 1 DIR 1 write the data from the READ POSITION commands to the directory 8. Repeat steps 4 through 7 for successive data sets until the tape is full or until there is no more data to be written.
Appendix B Directory Support 11. LBOT MASTER DIR Rewind the tape to LBOT. This creates an EOD mark at the end of the master directory (EOD 1) that overwrites most of the 12-MByte pad. EOD 1 PAD LFM DS 1 DIR 1 . . . DS n DIR n EOD 2 ← 1. Rewind 2. Write the master directory Note: After writing the master directory, be sure to rewind the tape or perform a space backward operation.
Appendix B Directory Support Accessing Data on a Directory Support Tape To use the LOCATE command to access the data written in the previous section, follow these steps: 1. LBOT MASTER DIR Read the master directory to determine the locations of the data set directories on the tape. EOD 1 PAD LFM DS 1 DIR 1 . . . DS n DIR n EOD 2 read master directory Note: 2.
Appendix B Directory Support 3. Once you have found a directory that lists the file you need, issue another LOCATE command to reach that file, using the READ POSITION data from the directory. 1. Issue LOCATE command LBOT MASTER DIR EOD 1 PAD LFM ... DS 2 DIR 2 ↑ 2.
Appendix B Directory Support Notes: May 1994 EXB-8205 and EXB-8505 (Standard and XL) B-13
C Data Cartridge Capacities This appendix lists capacities and track and physical block counts for the different sizes of EXATAPE™ data cartridges. It also describes how the CTS autosizes these different data cartridge sizes.
Appendix C Data Cartridge Capacities EXATAPE Capacities Exabyte strongly recommends that you use EXATAPE data-grade metal-particle media with your EXB-8205 or EXB-8505. Do not attempt to use “Hi-8” metal-particle or any type of metal-evaporative tape. These tapes will be ejected automatically by the CTS. EXATAPE is specifically controlled for use in data storage environments and offers extended durability, long-term archivability, and greater reliability.
Appendix C Data Cartridge Capacities Track and Physical Block Counts Tables C-2 and C-3 list the following information for EXATAPE data cartridges written in 8500c, 8500, 8200c, and 8200 formats: The number of tracks and 1,024-byte physical blocks between LBOT and LEOT The approximate number of tracks and 1,024-byte physical blocks between LEOT and PEOT See Chapter 1 for explanations of LBOT, LEOT, and PEOT.
Appendix C Data Cartridge Capacities Autosizing of Data Cartridges Autosizing is the process that occurs during a load operation when the CTS spaces forward from the physical beginning of tape (PBOT) to the logical beginning of tape (LBOT) and determines the length of the tape in use. The CTS accurately determines the length of the EXATAPE 15m, 54m, and 160m XL cartridges during the load operation.
D SCSI Bus Message Processing and Error Recovery This appendix describes message processing and error handling by the CTS and the appropriate initiator response when error conditions are detected during different SCSI bus phases. The errors and responses are separated into two categories: Errors and responses for initiators that support only the Command Complete message. Errors and responses for initiators that support messages in addition to the Command Complete message.
Appendix D SCSI Bus Message Processing and Error Recovery SCSI Bus Error Recovery (Initiators Supporting the Command Complete Message Only) This section describes the actions to be taken by the initiator and the CTS when a SCSI bus parity error occurs. The information in this section applies to those initiators that support the Command Complete message only.
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing / SCSI Bus Error Recovery (Initiators Supporting Other Messages) This section describes CTS message processing and SCSI bus error recovery for initiators supporting messages in addition to Command Complete. It includes a number of charts showing the actions that the CTS will take in response to each message it receives from the initiator.
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing after the Selection Phase Figure D-1 shows that the CTS will only accept three legal messages immediately after the Selection phase (Abort, Reset, and Identify). Parity Error in the Selection Phase When parity checking is enabled and the CTS detects a parity error during the Selection phase, it stays in the Message Out phase until the Attention signal goes low. Then, it retries by going to the Message Out phase again.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Selection Transition to: Message Out Abort Reset All others Go Bus Free Go Bus Free Go Bus Free Executewarmreset Identify No IsDisconnectbit set? Yes Disallowdiscon nects Allowdisconnects No Yes IsLUNvalid (equal0)? SetinvalidLUNflag ClearinvalidLUNflag No Yes IsAttentionhigh? StayinMessageOut phase Go toCDBInphase Figure D-1 Message processing after the Selection phase May 1994 EXB-8205 and EXB-8505 (Standard
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in the Message Out Phase Figure D-2 shows the message sequences for Message Out bytes received during a previously initiated Message Out phase. Note that Message Reject and Initiator Detected Error messages received after a previous Message Out phase are treated as catastrophic errors committed by the initiator.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Message Out Transition to: Message Out Abort Does initiatorowncur rent process? Yes Identify No Yes IsDisconnectbit set? Allowdisconnects No Disallowdiscon nects Abort process Go Bus Free Continue processing Reset No Operation Go Bus Free Continue processing Extended Message Process Extendedmessage Executewarmreset All others Message Reject or Initiator Detected Error Send MessageRejectIn Setsense keyto AbortedCo
Appendix D SCSI Bus Message Processing and Error Recovery Processing during the Command Out Phase Figure D-3 shows how CDB bytes are processed. Note that the Group Code in the CDB’s first byte determines how many CDB bytes are to be transmitted. If the initiator asserts the Attention signal during the Command In phase, the CTS waits until all CDB bytes have been received and then goes to the Message Out phase.
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in the Message Out Phase after Command Phase Figure D-4 shows how messages are processed after the Command phase and before any Data phase. This processing is the same as that in Figure D-2. Message sequences that are legal before the CDB is received are also legal after the CDB is received.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Message Out Transition to: Message Out Abort Does initiatorowncurr ent process? Yes Identify No IsDisconnectbit set? Yes Allowdisconn ects No Disallowdisconn ects Abort process Go Bus Free Continue processin g Reset No Operation Go Bus Free Continue processin g Extended Message ProcessExtendedmessage Execute warmreset All others Message Reject or Initiator Detected Error Send MessageRejectIn Setsensekeyto Aborte
Appendix D SCSI Bus Message Processing and Error Recovery Processing of Extended Message Out Figure D-5 shows how Extended Message Out messages are processed. Note that the Attention signal must coincide with the message byte numbering sequence. The CTS responds to the initiator’s Synchronous Data Transfer Request with a transfer period of xx or 32h (200 nanoseconds), whichever is larger (slower), and a REQ/ACK offset of yy or Bh (11), whichever is smaller.
Appendix D SCSI Bus Message Processing and Error Recovery Extended Message Processing (message bytes out) Receivemessagebyte00 Isit01handisthe Attentionsignalasserted? No Yes Receivemessagebyte01 Isit03handisthe Attentionsignalasserted? No Yes Receivemessagebyte02 Isit01handisthe Attentionsignalasserted? No Yes Receivemessagebyte03 IstheAttention signalasserted? No Yes Receivemessagebyte04 IstheAttention signalasserted? Yes Go toMessageIn No Send MessageReject Go toMessageIn Send Synchron
Appendix D SCSI Bus Message Processing and Error Recovery Processing of Extended Message In Figure D-6 shows how the Extended Message In messages are processed. The CTS executes this message sequence in response to an initiator’s Synchronous Data Transfer Request. Parity Error in Extended Message In If the initiator detects a parity error in the Synchronous Data Transfer Request byte being sent by the CTS, it responds by sending a Message Parity Error message to the CTS.
Appendix D SCSI Bus Message Processing and Error Recovery Extended Message Processing (message bytes in) Send messagebyte00;value=01h Send messagebyte01;value=03h Send messagebyte02;value=01h Send messagebyte03;value=xx Send messagebyte04;value=yy No IsAttentionasserted? Continue processing Yes Yes Isthemessageouta MessageParityError message? No Go toMessageOut Figure D-6 Message processing for Synchronous Data Transfer Request message D-14 EXB-8205 and EXB-8505 (Standard and XL) 510503
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in Data Out Phase (WRITE Command) Figure D-7 shows how each message is processed during the Data Out phase of a WRITE command. Parity Error in User Data Associated with WRITE Command When parity checking is enabled and the CTS detects a parity error in the logical blocks of user data received from the initiator, the CTS aborts the data transfer. The data block containing the parity error is not written to tape.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Data Out Transition to: Message Out (write data to tape) Abort Does initiatorowncur rent process? Identify No IsDisconnectbit set? Yes Yes No Allowdisconnects Disallowdiscon nects Abort process Go Bus Free Continue processing Reset No Operation Go Bus Free Extended Message Continue processing Process ExtendedMessage Executewarmreset All others Message Reject Abort process Setsense keyto AbortedCommand(Bh) Send
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in Data Out Phase (Information Commands) Figure D-8 shows how messages are processed during the Data Out phase for commands other than WRITE (for example, MODE SELECT). Parity Error in Data Out Phase (Information Command) When parity checking is enabled and the CTS detects a parity error in the data sent after the MODE SELECT CDB, it goes to the Message In phase and sends a Restore Pointers message.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Data Out (Information Command) Transition to: Message Out (for example, MODE SELECT) Abort Identify Does initiatorowncur rent process? No Yes IsDisconnectbit set? Yes Allowdisconnects No Disallowdiscon nects Abort process Go Bus Free Continue processing Reset No Operation Go Bus Free Continue processing Extended Message Process ExtendedMessage Executewarmreset Message Reject All others Setsense keyto AbortedComman
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in Data In Phase (READ Command) Figure D-9 shows how messages are processed during the Data In phase of a READ command (that is, when the initiator asserts the Attention signal while it is receiving user data from the CTS). Parity Error in Data Associated with READ Command If the initiator detects a parity error in data transferred from the CTS during a READ command, it should assert the Attention signal.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Data In Transition to: Message Out (Read data fromtape) Abort Identify Does initiatorowncur rent process? No IsDisconnectbit set? Yes Yes Allowdisconnects No Disallowdiscon nects Abort process Go Bus Free Continue processing Reset No Operation Go Bus Free Continue processing Extended Message Process ExtendedMessage Executewarmreset Initiator Detected Error All others Abort process Abort process Setsense keyto Abo
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in Data In Phase (Information Commands) Figure D-10 shows how messages are processed during the Data In phase for commands other than READ (for example, INQUIRY, REQUEST SENSE, and MODE SENSE). Parity Error in Data In Phase (Information Commands) If the initiator detects a parity error in data transferred from the CTS during a REQUEST SENSE, MODE SENSE, READ POSITION, or INQUIRY command, it should assert the Attention signal.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Data In (Information Command) Transition to: Message Out (for example, INQUIRY, REQUESTSENSE) Abort Does initiatorowncurr ent process? Yes Identify No IsDisconnectbit set? Yes Allowdisconn ects No Disallowdisconn ects Abort process Go Bus Free Continue processin g Reset No Operation Go Bus Free Continue processin g Extended Message ProcessExtendedMessage Execute warmreset Message Reject Initiator Detected Error Al
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing In Status In Phase Figure D-11 shows how messages are processed during the Status In phase. Note that attempts to change the physical path characteristics are not processed. Initial Phase: Status In Transition to: Message Out Abort Does initiatorowncur rent process? Yes Identify* No Yes *Thismessageis allowed,butwill notaffectthe disconnect priviledge.
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing in Message In Phase (Command Complete) Figure D-12 shows how messages are processed while the CTS is attempting to send the Command Complete message. Parity Error Sending the Command Complete Message In If the initiator detects a parity error during the Command Complete Message In phase, it sends a Message Parity Error message to the CTS. The CTS responds by re-sending the Command Complete message.
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing after Reselection Figure D-13 shows how messages are processed after the CTS has reselected the initiator and sent the Identify message in. Note that if the initiator sends the CTS a Message Reject message, this will be treated as a catastrophic error committed by the initiator.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Reselection withIdentifyIn Transition to: Message Out Abort Identify Does initiatorowncurr ent process? No Yes IsDisconnectbit set? Yes No Allowdisconn ects Disallowdisconn ects Abort process Go Bus Free Continue processin g Reset No Operation Go Bus Free Continue processin g Extended Message ProcessExtendedMessage Execute warmreset All others Message Parity Error Abort process Send MessageRejectIn Send Identify
Appendix D SCSI Bus Message Processing and Error Recovery Message Processing during Disconnect Sequence Figure D-14 shows how messages are processed while the CTS is executing the “disconnect” sequence. Note that attempts to change the physical path characteristics are not allowed. Also, the disconnect sequence may be aborted if the initiator sends a Message Reject message.
Appendix D SCSI Bus Message Processing and Error Recovery Initial Phase: Message In sending Save Data Pointers or Disconnect Transition to: Message Out Abort Does initiatorowncurr ent process? Reset No Operation Go Bus Free Continue processin g No Execute warmreset Yes Abort process Extended Message Go Bus Free ProcessExtendedMessage Message Reject Message Parity Error Disallowdisconn ects All others Send MessageRejectIn SkipDisconnectphase Send SaveData Pointers orDisconnectmessage again
E Error Information This appendix is a reference for: The Additional Sense Codes (ASCs) and Additional Sense Code Qualifiers (ASCQs) returned by the REQUEST SENSE (03h) command. These codes provide additional information about each sense key. The Fault Symptom Codes (FSCs) returned by the REQUEST SENSE command. These Exabyte-unique codes can be used to determine the nature of hardware and software errors and other events. Recommended recovery procedures for each FSC are also provided.
Appendix E Error Information REQUEST SENSE Information This section lists the possible combinations of values for the Additional Sense Code (ASC) and the Additional Sense Code Qualifier (ASCQ) fields in the Extended Sense Bytes returned by the REQUEST SENSE (03h) command. Each ASC and ASCQ combination is correlated with one or more of the Exabyte-unique Fault Symptom Codes (FSC) that are returned as byte 28 in the Extended Sense Bytes.
Appendix E Error Information Sense Key = 1h (Recovered Error) Table E-2 REQUEST SENSE information for Sense Key 1h ASC (Byte 12) ASCQ (Byte 13) 5Bh 02h Explanation Log parameter overflow (a cumulative counter reached its maximum value of all FFs). Related FSC ECh Sense Key = 2h (Not Ready) Table E-3 REQUEST SENSE information for Sense Key 2h ASC (Byte 12) ASCQ (Byte 13) 04h 00h Logical unit not ready. No additional sense information. Refer to the Fault Symptom Code.
Appendix E Error Information Sense Key = 3h (Medium Error) Table E-4 REQUEST SENSE information for Sense Key 3h ASC (Byte 12) ASCQ (Byte 13) 00h 02h PEOT or PEOP was encountered during a space or locate operation. 03h 02h Excessive write errors. 09h 00h Tracking error. 0Ch 00h LBOT failure—unable to write tapemark tracks in 8200 format. 11h 00h An uncorrectable block was encountered during a read, space, or locate operation.
Appendix E Error Information Sense Key = 4h (Hardware Error) Table E-5 REQUEST SENSE information for Sense Key 4h ASC (Byte 12) ASCQ (Byte 13) 00h 00h Undetermined hardware error. 08h 01h Logical unit communication timeout. 08h 02h Logical unit communication parity error. 0Ch 00h Hardware failure—Head sync error during write. 11h 00h A hardware error was detected during a read operation. 11h 02h Read decompression CRC failed. 19h 15h 01h Servo hardware failure.
Appendix E Error Information ASC (Byte 12) ASCQ (Byte 13) 3Dh 00h Illegal bit set in Identify message. DAh 4Eh 00h Overlapped commands attempted—Bad initiator-target-LUN (ITL) nexus. D8h 50h 01h Write append position error, or illegal position to format partitions. 53h 02h Media removal prevented. D2h 81h 00h Mode mismatch. Fixed/variable. D3h 82h 00h The command requires no tape, but a tape is loaded (SEND DIAGNOSTICS).
Appendix E Error Information Sense Key = 7h (Data Protect) Table E-8 REQUEST SENSE information for Sense Key 7h ASC (Byte 12) ASCQ (Byte 13) 27h 00h Explanation The tape is write protected. Related FSC 03h, 27h, 4Ch Sense Key = 8h (Blank Check) Table E-9 REQUEST SENSE information for Sense Key 8h ASC (Byte 12) ASCQ (Byte 13) 00h 05h Explanation End of data encountered on a read operation.
Appendix E Error Information Sense Key = Bh (Aborted Command) Table E-11 REQUEST SENSE information for Sense Key Bh ASC (Byte 12) ASCQ (Byte 13) 00h 00h No additional sense information. Refer to the Fault Symptom code. 08h 02h IPORT write or read parity error. 10h 00h Compression Integrity Check failed. 43h 00h Message error. 47h 00h The command was aborted because of a SCSI bus parity error. E6h 48h 00h Initiator detected error.
Appendix E Error Information Fault Symptom Codes This section lists the Fault Symptom Codes that may be returned by the REQUEST SENSE (03h) command. The Fault Symptom Code is returned as byte 28 in the Extended Sense Bytes. It is an Exabyte-unique byte that specifies the reason for the most recent Check Condition status. Note: You can also use the Fault Symptom Code field to determine the location of errors in data sent with the MODE SELECT (15h) command and the LOG SELECT (4Ch) command.
Appendix E Error Information Fault Symptom Code Descriptions Table E-13 Fault Symptom Codes FSC SK ERP 02h 5h 11 A WRITE command was received when the tape was not at a legal position to write. 03h 7h 5 A WRITE command was received when the data cartridge was write protected. 04h 0h 11 LEOT or LEOP was encountered during the current write operation (the command may have terminated early). 05h Bh 11 The write operation was aborted, as requested.
Appendix E Error Information FSC SK ERP 1Dh 0h 11 A setmark was encountered during a read or verify operation. 26h 5h 11 A WRITE FILEMARKS command was received when the tape was not at a legal position to write. 27h 7h 5 A WRITE FILEMARKS command was received when the data cartridge was write protected. 28h 0h 11 LEOT or LEOP was encountered during or before the write filemarks operation—the filemark was written. 31h 0h 11 A setmark was encountered during a space operation.
Appendix E Error Information FSC SK ERP 64h 3h 11 Bank 1 of control load image was not valid when loading firmware. 65h 3h 11 The EEPROM load image was not valid when loading firmware. 66h 3h 11 The boot code did not allow a load from tape, or the code version was not supported by the boot code. 67h 4h 12 One of the memories could not be programmed. 68h 4h 12 A Hardware Error occurred while loading new firmware. 69h 3h 3 The CRC in the load image in the buffer was incorrect.
Appendix E Error Information FSC SK ERP Description A1h 4h 8, 12 Hardware failure—Head sync error during write. A2h 4h 8, 12 Underrun error during write. A3h Bh 13 IPORT write buffer parity error. A4h 4h 8, 12 DPORT write buffer parity error. A5h 4h 8 Buffer positioning lost during write abort process. A6h Bh 13 IPORT read buffer parity error. A7h 4h 8, 12 DPORT read buffer parity error. A8h 4h 8, 12 PPORT parity error. ABh 4h 9, 8, 3, 6 Servo timed out.
Appendix E Error Information FSC SK ERP CAh 6h 3 Unit Attention–Log threshold met. (For more information about this error, look at the Log Parameter Page Code and Log Parameter Code bytes in the REQUEST SENSE data.) CBh 6h 3 Unit Attention–Log parameter changed. CCh 5h 4 Parameter List Length error in the MODE SELECT CDB. CDh 5h 4 Illegal Op Code. CEh 5h 4 Invalid field or reserved bits set in the CDB. CFh 5h 4 The LUN is not supported.
Appendix E Error Information FSC SK ERP Description E7h Bh 11 The initiator sent an Abort or Initiator Detected Error message during a read operation and the command was aborted. EAh 5h 4 Conflict between Density Code and Data Compression Page in MODE SELECT. EBh Bh 11 Operation illegal during write buffer sequence. ECh 1h 10, 11 FAh 4h 15 The CTS’s serial number is invalid or blank. FCh 4h 15 Head sync value in EEPROM is out of range.
Appendix E Error Information Error Recovery Procedures Table E-14 describes the error recovery procedures (ERPs) recommended for each Fault Symptom Code listed in Table E-13. Note: If two or more ERP codes are listed for the Fault Symptom Code, perform the action for the first code, then perform the action for the second code, and so on. Table E-14 Recommended error recovery procedures ERP Recommended Error Recovery Procedure 1 Issue a REWIND command and retry the operation.
Glossary May 1994 8200 format A non-compressed data format written and read by all Exabyte 8mm CTSs. 8200c format A compressed data format written and read by the EXB-8205, EXB-8205XL, EXB-8505, EXB-8505XL, and EXB-8500c. 8500 format A non-compressed data format written and read by the EXB-8505, EXB-8505XL, EXB-8500c, and EXB-8500. 8500c format A compressed data format written and read by the EXB-8505, EXB-8505XL, and EXB-8500c. ANSI American National Standards Institute.
Glossary ASCQ Additional Sense Code Qualifier. This byte is returned as byte 13 of the REQUEST SENSE extended sense data. The ASCQ, in conjunction with the Additional Sense Code (ASC), provides additional information about each sense key. ATN Attention signal. The SCSI bus signal asserted by the initiator to indicate that it has a message to transmit to the target. AWG b Binary (base 2) numbering system. BOT Beginning of tape. BSY Busy bus condition.
Glossary early warning ECC ECMA EEPROM EPROM May 1994 The logical end of tape (LEOT) or logical end of partition (LEOP). Error correction code. European Computer Manufacturers Association. Electrically erasable programmable read-only memory. Erasable programmable read-only memory. EOD End of data. EOP End of partition. EOT End of tape. EXATAPE A data-grade, metal particle, rewritable 8mm data cartridge that is recommended for use in all Exabyte 8mm CTSs.
Glossary EXB-8500c The EXB-8500c 8mm Cartridge Tape Subsystem. The EXB-8500c is physically similar to the EXB-8500, but offers data compression as an option. Assuming an average ratio of 2:1, the EXB-8500c can store up to 10.0 gigabytes of data on an EXATAPE 112m 8mm Data Cartridge. EXB-8505 The EXB-8505 8mm Cartridge Tape Subsystem. The EXB-8505 is a 5.25-inch half-high 8mm CTS that can store up to 10.0 gigabytes of data on an EXATAPE 112m 8mm Data Cartridge, assuming an average 2:1 compression ratio.
Glossary ISO International Standards Organization. KByte Kilobyte. LBOP Logical beginning of partition. LBOT Logical beginning of tape. LEOP Logical end of partition. LEOT Logical end of tape. LSb Least significant bit. LSB Least significant byte. LUN Logical unit number. MByte mm motion threshold Megabyte. Millimeter (0.03937 inches). During a start/stop write operation, the minimum amount of data that must be in the CTS’s buffer before data in the buffer will be written to tape.
Glossary PBOP Physical beginning of partition. PBOT Physical beginning of tape. PEOP Physical end of partition. PEOT Physical end of tape. POST Power-on self-test, which is the process that occurs when the CTS performs its initial power-on diagnostics. ready The state of the CTS when it is ready to process commands. reconnect reconnect threshold The function that occurs when the target arbitrates and reconnects to an initiator after a disconnect.
Glossary signal release status Information sent from the target to the initiator upon completion of a command. target A bus device (usually a peripheral device) that performs an operation requested by an initiator. The EXB-8205 and EXB-8505 are targets. µm µs or µsec May 1994 When a signal is not driven by a bus but is biased by the cable terminators to the false state. Micrometer (0.00003937 inches). Microsecond.
Glossary Notes: G-8 EXB-8205 and EXB-8505 (Standard and XL) 510503
Index ! 8200 format appending to 10-67 filemarks 3-15 to 3-16 logical block structure 1-11 physical block structure 1-11 reading 10-67 writing 10-66 8200c format appending to 10-65 to 10-66 filemarks 3-15 to 3-16 logical block structure 1-11 physical block structure 1-11 reading 10-66 writing 10-65 8500 format appending to 10-64 filemarks 3-15 to 3-16 logical block structure 1-11 physical block structure 1-11 reading 10-65 writing 10-64 8500c format appending to 10-63 filemarks 3-15 to 3-16 logical block st
Index C CDB 2-9 to 2-11 Check Condition status 2-13 cleaning the CTS CLN bit 18-10 CLND bit 18-10 LED indicators for 1-16 REQUEST SENSE indicators for 18-10 UCLN bit 18-10 CLN (clean) bit, REQUEST SENSE 18-10 CLND (cleaned) bit, REQUEST SENSE 18-10 Command Complete (00h) message 2-16 command descriptor block (CDB) 2-9 to 2-11 commands field definitions, general 2-9 to 2-11 format errors 2-11 general format 2-7 to 2-8 status byte returned 2-12 to 2-14 ERASE 4-1 to 4-4 INQUIRY 5-1 to 5-10 LOAD/UNLOAD 6-1 to
Index E EBD bit 10-22, 10-53 EEPROM options Allow position past EOD B-1 Button action 1-14, 3-3 Command queuing 3-36, 6-3 Default write format 3-10 to 3-11 defined A-1 to A-32 directory support 3-31, B-1 EBD unit size 10-22, 10-53 MODE SELECT and MODE SENSE 10-12 ordering A-2 end-of-data mark see EOD EOD described 1-10 to 1-11 detected during locate 7-7 detected during read 12-6 detected during space 22-7 detected during verify 24-6 spacing to 22-3 Equal (Ch) sense key 18-6 ERASE command 4-1 to 4-4 ERP cod
Index I Identify message 2-21 Illegal Request (5h) sense key ASC and ASCQ values for E-5 to E-6 described 18-5 LOCATE 7-9 READ 12-10 SPACE 22-10 VERIFY 24-9 WRITE 25-13 Initiator Detected Error (05h) message 2-19 INQUIRY command description 5-1 to 5-10 field definitions 5-2 to 5-3 Standard Inquiry Data 5-4 to 5-7 Supported Vital Product Data Page 5-8 Unit Serial Number Page 5-9 L M LBOP 3-24 to 3-25 LBOT 1-10 LEDs location 1-13 states indicated by 1-15 to 1-16 LEOP 3-24 to 3-25 LEOT defined 1-11 detecte
Index MODE SELECT command (cont.
Index PEOT defined 1-11 detected during locate 7-8 detected during read 12-7 detected during space 22-8 detected during verify 24-6 detected during write 25-11 detected during write filemarks 27-6 PF field, MODE SELECT 10-4 physical beginning of tape see PBOT physical block counts C-3 physical blocks 1-11, 3-12 to 3-14 physical end of tape see PEOT physical path communications 2-1 to 2-22 physical track structure 1-6 to 1-8 power-on defaults 1-17 power-on reset 3-34 PREVENT/ALLOW MEDIUM REMOVAL command des
Index S T Save Data Pointer (02h) message 2-18 SCSI bus phases 2-2 to 2-3 bus reset 3-35 command descriptor block 2-9 to 2-11 command format 2-7 to 2-8 command format errors 2-11 command status 2-12 to 2-14 commands 2-4 to 2-6 error recovery D-1 to D-29 instruction trace table 16-8 message processing D-1 to D-29 message system 2-15 to 2-22 overview 2-2 to 2-3 search fields 1-13 SEND DIAGNOSTIC command description 21-1 to 21-8 diagnostic tests 21-4 field definitions 21-3 sense key values 18-4 to 18-6, E-1
Index V variable-length logical blocks 10-20 Vendor Unique Parameters Page 1 10-51 to 10-55 Vendor Unique Parameters Page 2 10-56 to 10-57 vendor-unique parameters (non-page format) 10-21 to 10-24 verification length incorrect 24-8 to 24-9 VERIFY command description 24-1 to 24-10 exceptions and errors 24-4 to 24-9 field definitions 24-2 to 24-3 Volume Overflow (Dh) sense key 18-6, E-8 W WRITE BUFFER command description 26-1 to 26-6 exceptions and errors 26-5 to 26-6 field definitions 26-4 to 26-5 WRITE co
