.................................. DDS-4 and DAT 72 Tape Drives and Autoloaders .................................. .................................. .................................. .................................. SCSI Interface Manual ..................................
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Contents Page iii Contents Introduction 1 Overview...................................................................................................................... 1 Drive Models ............................................................................................................... 1 About This Manual ...................................................................................................... 1 SCSI Interface Description 2 Overview...............................................
Page iv DDS-4 SCSI Interface Manual, Rev. B Message-Out Phase ...........................................................................................15 Command Descriptor Block.......................................................................................16 Logical Unit Support ..................................................................................................17 SCSI Message Descriptions and Definitions.............................................................
Contents Page v ERASE Command Descriptor Block................................................................... 37 Command Descriptor Block Field Description.................................................... 37 Completion Status .............................................................................................. 37 EXCHANGE MEDIUM (AutoLoader Only) (A6h) ...................................................... 39 EXCHANGE MEDIUM Command Descriptor Block.........................................
Page vi DDS-4 SCSI Interface Manual, Rev. B MODE SELECT (15h) ...............................................................................................75 MODE SELECT Command Descriptor Block .....................................................75 Command Descriptor Block Field Description ....................................................76 MODE SELECT Parameters...............................................................................76 Parameter List Header Field Descriptions ..............
Contents Page vii Completion Status ............................................................................................ 115 READ ELEMENT STATUS (Autoloader Only) (B8h).............................................. 116 READ ELEMENT STATUS Command Descriptor Block ................................. 116 Element Status Data ......................................................................................... 116 Element Status Data Header ...........................................................
Page viii DDS-4 SCSI Interface Manual, Rev. B Definition of Sense Keys...................................................................................138 Additional Sense Code and Code Qualifier ......................................................138 Vendor-Specific Code Qualifiers.......................................................................143 Completion Status.............................................................................................148 RESERVE UNIT (16h / 56h)..........
Contents Page ix WRITE DATA BUFFER Command Descriptor Block ....................................... 168 Command Descriptor Block Field Descriptions ................................................ 169 WRITE DATA BUFFER Data Header............................................................... 169 Completion Status ............................................................................................ 170 WRITE FILEMARKS (10h) ...........................................................................
Introduction Page 1 1 Introduction Overview The Seagate DDS-4 and DAT 72 DAT drives are designed for computer environments requiring high performance, high capacity data storage. These drives are available in 3.5-inch or 5.25-inch internal configurations or as an external subsystem. The Autoloaders contain a DDS-4 or DAT 72 drive with an enclosure and tape manipulation mechanism. Seagate DDS-4 and DAT 72 drives contain an embedded Small Computer Systems Interface (SCSI) controller.
Page 2 DDS-4 SCSI Interface Manual, Rev. B SCSI Interface Description 2 Overview The Seagate DDS-4 and DAT 72 drives are designed to operate with the Small Computer System Interface (SCSI) bus. This chapter discusses SCSI bus operation as it pertains to drive functions. SCSI is a standard interface established to support peripheral equipment such as printers, tape drives, magnetic disks, optical disks for microcomputers and other computer systems.
SCSI Interface Description Page 3 Signal Descriptions The drive SCSI interface consists of eighteen signals. Nine are control lines and eighteen are data lines. Data lines include the parity signal option. These signals are described in the following table. Signal Name Description -BSY -SEL Busy OR-tied signal used to show that the data bus is in use Select Signal used by an Initiator to select a Target or by a Target to reselect an Initiator.
Page 4 DDS-4 SCSI Interface Manual, Rev. B Command Set Description The following table shows the SCSI commands for sequential access devices implemented by the drive and autoloader.
SCSI Interface Description Page 5 ANSI X3.131, 199x Conformance Statement (SCSI-2) General features • Disconnect/reconnect, arbitration (required in SCSI-2). • Supports LVD and single-ended drivers. • Fixed and variable block transfer lengths. • Hard reset. • Synchronous data transfers • Parity implemented (switch option). • Space blocks, filemarks, EOD, and setmarks. • Supports third-party reservation • Log Sense and Log Select for managing soft errors reporting.
Page 6 DDS-4 SCSI Interface Manual, Rev.
SCSI Interface Description Page 7 Data-transfer operations on the SCSI bus are either asynchronous or synchronous. Asynchronous data transfer operations follow a defined request/acknowledge (REQ/ACK) handshake protocol. Two eight-bit bytes of information can be transferred with each REQ/ACK handshake. The default data transfer mode is asynchronous. Synchronous data transfer operations are initiated through the SYNCHRONOUS DATA TRANSFER REQUEST message from the Initiator.
Page 8 DDS-4 SCSI Interface Manual, Rev. B Figure 2-1 Phase Sequencing with Arbitration RESET CONDITION BUS FREE PHASE ARBITRATION PHASE SELECTION OR RESELECTION PHASE COMMAND, DATA, STATUS, OR MESSAGE PHASE Arbitration is won by the highest priority SCSI device when both BSY and SEL are asserted and a delay of at least 1200 nSec (1 bus clear delay + 1 bus settle delay) occurs before the Arbitration Phase ends and the Selection Phase begins.
SCSI Interface Description Page 9 2. The SCSI device waits a minimum of one bus free delay of 800 nSec after detection of a Bus Free Phase before driving any signal. The Bus Free Phase occurs after BSY and SEL are both false for a bus settle delay of 400 nSec. 3. Following the 800 nSec Bus Free Delay in Step 2, the SCSI device Arbitrates for the SCSI bus by asserting both BSY and its own SCSI ID; however, the SCSI device does not assert a BSY and its SCSI ID if more than a bus settle delay (1.
Page 10 DDS-4 SCSI Interface Manual, Rev. B For example, the Initiator can select a tape drive to begin an operation, or the tape drive can reselect an Initiator to continue an operation previously disconnected. The tape drive does not disconnect from the bus unless the host asserted the host ID bit during selection and the host sent an Identify message of C0h. The Selection and Reselection Phases can be terminated for either of the following reasons: • A Selection/Reselection time-out occurs.
SCSI Interface Description 1 Page 11 The host supports disconnects. The drive disconnects from the SCSI bus appropriately for the command in progress to relinquish the bus for other units. Note: LUN = 1 is legal for Autoloader drives only. Information Transfer Phases The Command, Data, Status, and Message Phases are grouped together as the Information Transfer Phases because they are all used to transfer data or control information on the SCSI bus.
Page 12 DDS-4 SCSI Interface Manual, Rev. B t3 t4 t5 The Initiator reads the data and parity signals after REQ is asserted and then signals its acceptance of the data by asserting the ACK. ACK goes low at the Target, and the Target de-asserts REQ. The REQ signal is false. The Initiator de-asserts ACK. After the ACK signal is high, the Target can continue the transfer by repeating the steps from t1.
SCSI Interface Description Page 13 Figure 2-5 Signals Used in Transfer from Initiator to Target Synchronous Data Transfer Both the Initiator and Target must send a SYNCHRONOUS DATA TRANSFER REQUEST (SDTR) message in order to set up synchronous data transfer parameters. The drives supports both SDTR WDTR extended (multibyte) messages.
Page 14 DDS-4 SCSI Interface Manual, Rev. B The minimum value fo the Transfer Period (25 nsec) is determined by the maximum burst transfer rate of the SCSI interface hardware of the drive and is 80 Mbytes per second (06h). The host must specify a Transfer Period that allows it to successfully receive data from the DAT drive during the Data In Phase. Transfer Period represents the actual transfer period, in nanoseconds, divided by 4.
SCSI Interface Description Page 15 Data Phase The Data Phase is subdivided into the Data-In and Data-Out Phases. Data-In Phase During the Data-In phase, the Target requests that data be sent to the Initiator from the Target. The Target asserts the I/O signal and de-asserts the C/D and MSG signals thus denoting the Data-In Phase. The REQ/ACK handshakes (Figure 2-4) then transfer the requested byte count.
Page 16 DDS-4 SCSI Interface Manual, Rev. B Command Descriptor Block A request to a peripheral device is performed by sending a Command Descriptor Block (CDB) to the Target. For several commands, the request is accompanied by a list of parameters sent during a Data Out Phase. If an invalid parameter is contained in the CDB, the drive terminates the command without altering the medium. The Seagate DDS-4 and DAT 72 drives implementation supports Group 0 and selected Group 1 and Group 2 commands.
SCSI Interface Description Page 17 Group Code* This field indicates which of eight possible SCSI command groups is specified. Seagate drives support Group 0. Command Code* This field indicates which of 32 possible command codes for a particular group code is specified. Logical Unit The LUN must be set to zero. Vendor Unique When set, these bits select vendor unique functions in specified commands.
Page 18 DDS-4 SCSI Interface Manual, Rev. B SCSI Message Descriptions and Definitions The SCSI message codes, descriptions, and directions are given in the following table. Each of these SCSI messages is supported by the Seagate DDS-4 drive.
SCSI Interface Description Page 19 The following table lists SCSI messages and their definitions. Hex Code 00h 02h 04h 05h 06h Message Definition Command Complete This message is sent from the drive to inform an Initiator that execution of a command terminated and that valid status was sent to the Initiator. After successfully sending this message, the drive goes to the Bus Free Phase by releasing BSY.
Page 20 DDS-4 SCSI Interface Manual, Rev. B Hex Code 0Bh 0Ch Message Linked Command complete with Flag Bus Device Reset Identify (80h disable Disconnect / Reconnect) (C0h enable Disconnect / Reconnect) Definition This message is sent from the DAT drive to inform an Initiator that execution of a linked command with the Flag bit set to one, is completed and that status was sent. The Initiator then sets the current pointers to the initial state of the next linked command.
SCSI Interface Description State or Phase Command Phase Page 21 Description If the drive detects a parity error while the host is transferring a CDB, the drive • Terminates the transfer. • Switches the host to the Status Phase and sends a Check Condition. • Switches the host to the Message In Phase and sends a Command Complete. • Sets the Sense Key = B and ASC/ASCQ = 47-00 (SCSI2 only).
Page 22 DDS-4 SCSI Interface Manual, Rev. B State or Phase Message Out Phase Description If the host is in the Message Out Phase and sends a message bytes and the drive detects a parity error, the drive: • attempts one retry then goes to Bus Free.
SCSI Interface Description Page 23 SCSI Status Code Descriptions and Definitions The status code format is shown in the following table. A status byte is sent from the DAT drive to the Initiator during the Status phase at the termination of each command unless the command is cleared by an Abort message, by a Bus Device Reset message, or by a Reset condition. BITS 7 6 5 Content 0 0 0 4 3 2 Status Code 1 0 The DAT drive uses the 4-bit status codes shown in the following table.
Page 24 DDS-4 SCSI Interface Manual, Rev. B Attention Condition The Attention Condition allows an Initiator to inform a Target that the Initiator has a message to send. The DAT drive may read this message at its convenience by performing a Message-Out phase. The Initiator creates the Attention Condition by asserting the ATN signal at any time except during the Arbitration or Bus Free phases. The DAT drive checks to see if ATN is set at every phase change.
SCSI Interface Description Page 25 If the Request Sense Command is received from an Initiator with a pending Unit Attention Condition before the DAT drive reports Check Condition Status, the DAT drive reports unit attention sense key and clears the Unit Attention Condition for that Initiator. Buffered Mode Buffered Mode allows the most efficient operation of the DAT drive. The drive defaults to Buffered mode.
Page 26 DDS-4 SCSI Interface Manual, Rev. B Disconnect/Reconnect Function When the drive is performing a task not requiring communication with the Initiator or when the DAT drive determines that a relatively long time has passed with no bus activity, it disconnects from the SCSI bus. Examples are: • When rewinding the tape. • When writing to the tape and the buffer is full. • When reading from the tape and the buffer is empty.
SCSI Interface Description Page 27 3. When the DAT drive has successfully reselected the Initiator, it sends an Identify Message to reestablish the path between the drive and the Initiator. This message is always 80h because the DAT drive is initiating the reselection and is always LUN 0. A Restore Pointers Message is implied when the DAT drive sends an Identify Message to the Initiator. The Initiator responds accordingly.
Page 28 DDS-4 SCSI Interface Manual, Rev. B Error Reporting Soft Errors Soft errors are generally tape-quality related and occur more frequently during write operations than during read operations. Soft errors indicate repeated attempts by the drive to read or write data on the tape. Some soft errors are normal, but an increase in the usual count can indicate deteriorating tape quality. If the soft error count remains higher than normal, clean the read/write heads.
SCSI Interface Description Page 29 When reading in variable mode, the host must know the size of the block to be read from the tape in advance in order to avoid causing the DAT drive to return a Check Condition with Incorrect Length indicated in the Sense data (ILI). Also, the data transfer may be truncated (cut off) when the recorded block does not match the transfer length in variable mode or the current block size in fixed mode.
Page 30 DDS-4 SCSI Interface Manual, Rev. B Move Medium Command The SMC Move Medium command moves a cassette from one address to another by specifying a Source Address and a Destination Address. Scorpion 240 requires that one of the addresses be 1, the DTE (drive). This command cannot be used to move a cassette from one magazine slot directly to another.
SCSI Interface Description Page 31 General Operation • The Reserve and Release commands may be addressed to either LUN, but affect both LUs as a unit. In other words, if an initiator has reserved either LU, then both LUs will reply with a status of Reservation Conflict to most SCSI commands from other initiators. This is departure from the SCSI standard, but it prevents the situation of each LU being reserved by a different initiator. • Busy status affects the Autoloader as one unit.
Page 32 DDS-4 SCSI Interface Manual, Rev. B When the magazine has been completely moved into the loader, the process of initialization begins, in which the magazine is scanned to determine which slots contain cassettes.
SCSI Interface Description Page 33 The following events will NEVER cause automatic loading: • Ejection of a cleaning cassette after cleaning failed. • Ejection of a data cassette by a SCSI Move Medium command. • Ejecting the last cassette in the magazine (i.e., the cassette in the highestnumbered occupied slot). Magazine Ejection The Eject button on the Autoloader can be used in two modes: regular and emergency eject. When the button is pressed for less than five seconds, a regular eject begins.
Page 34 DDS-4 SCSI Interface Manual, Rev. B 3 Commands Introduction This chapter describes the SCSI commands for the Seagate DDS-4 and DAT 72 tape drives. Command Reference List This chapter describes the implementation of the ANSI SCSI command specifications. The following table lists the commands numerically by opcode. Commands specific for the AutoLoader are noted.
Commands Page 35 Conventions The commands in this chapter are listed in alphabetical order. Each command is described; its Command Descriptor Block (CDB) illustrated; and the Completion Status is given. Bits and fields defined in the ANSI SCSI-2 document that are not used by the drive are not described in this document. Rather, those bits and fields are shown as 0, 1, or X (ignores), as appropriate. Bits and fields that are supported by the drive are described.
Page 36 DDS-4 SCSI Interface Manual, Rev. B Command Descriptor Block Field Descriptions The command descriptor block fields are described in the following table. Field Name Byte Bits Description Group Code 0 5-7 This field indicates the SCSI command groups used Command Code * 0 0-4 This field indicates which of 32 command codes is sent. NOTE: The Group Code and Command Code are used together to indicate the operation code. Logical Unit 1 5-7 The LUN must be set to zero.
Commands: Erase (19h) Page 37 ERASE (19h) The ERASE command creates an EOD (end-of-recorded data) marker at the current position of the tape when the command is issued, thus rendering the remainder of the tape unreadable. ERASE Command Descriptor Block The following table shows the layout of the CDB.
Page 38 DDS-4 SCSI Interface Manual, Rev. B EXCHANGE MEDIUM (AutoLoader Only) (A6h) The EXCHANGE MEDIUM command provides a means to exchange the cartridge in the source element with the cartridge located in the drive. This command provides the initiator a single-command alternative to two MOVE MEDIUM commands when removing a cartridge from the DAT drive and inserting another cartridge into the DAT drive. EXCHANGE MEDIUM Command Descriptor Block The following table shows the layout of the CDB.
Commands: Exchange Medium (A6h) Page 39 Completion Status The following table lists the completion status for the EXCHANGE MEDIUM command. Code Message 00h Good Status 02h Check Condition Description • • The cartridges have been moved to the specified destinations. the cartridge in the drive is positioned at BOT. The drive is ready for another command. Extended Sense Byte 02h Code Message Description 02h Not Ready No magazine is present.
Page 40 DDS-4 SCSI Interface Manual, Rev. B INITIALIZE ELEMENT STATUS (AutoLoader Only) (07h) The INITIALIZE ELEMENT STATUS command causes the AutoLoader to eject the cartridge that is in the DAT drive (if any) and return it to the slot in the magazine. Then the magazine is initialized, checking each element for cartridges or any other status relevant to that element.
Commands: Inquiry (12h) Page 41 INQUIRY (12h) The INQUIRY command requests that the drive return parameter information. If an INQUIRY command is received from an Initiator with a pending Unit Attention Condition (before the drive reports Check Condition status), the drive performs the INQUIRY command and does not clear the Unit Attention Condition. INQUIRY Command Descriptor Block The following table shows the layout of the CDB.
Page 42 DDS-4 SCSI Interface Manual, Rev. B Standard INQUIRY Data Format The following table shows the standard data format for the INQUIRY command.
Commands: Inquiry (12h) Page 43 The VPD pages supported are as follows: Byte Description 0 1 2 3 4 5 6 7 8 Peripheral Device Type Page Code (00h) Reserved Page Length (05h) Supported Pages (00h) Firmware Designation Page (03h) Drive Serial Number Page (80h) Controller Firmware Revision Page (C0h) Drive Firmware Revision Page (C1h) The Firmware Designation Page (03h) is defined as follows: Byte Description 0 1 2 3 4-11 12-15 16-31 Peripheral Device type Page Code (03h) Reserved Page Length (1Ch) Res
Page 44 DDS-4 SCSI Interface Manual, Rev. B INQUIRY Drive Serial Number Data Format Page The following table describes the drive serial number, which is sent from the drive to the host as data formatted in a parameter list.
Commands: Load/Unload (1Bh) Page 45 LOAD/UNLOAD (1Bh) The LOAD/UNLOAD command requests that the DAT drive enable or disable the logical unit for further operations. When a LOAD command is executed, the tape is positioned to LBOT and made ready for the next command. When an UNLOAD command is executed, the tape positions to BOT, and the cartridge is ejected without an error condition. The UNLOAD command ejects the cartridge even if a PREVENT MEDIA REMOVAL command is in effect.
Page 46 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the LOAD/UNLOAD command is shown in the following table. Code Message 00h Good Status Load = 1 (Load) Load = 0 (Unload) 02h Description • • • • • • The tape is positioned to the BOT of the current partition. The drive remains in any previously set modes. The drive is ready to perform any appropriate command. The tape is position to BOT and ejected. The drive remains in any previously set modes.
Commands: Locate (2Bh) Page 47 LOCATE (2Bh) The LOCATE command is used to position the tape to the specified block address in the specified partition. Before the locate operation is performed, all buffered data, filemarks, and setmarks are transferred to tape. On completion, the logical position is before the specified location. LOCATE Command Descriptor Block The following table shows the layout of the CDB.
Page 48 DDS-4 SCSI Interface Manual, Rev. B LOCATE and the BT Bit Assume that the data was written on the tape as shown in the following table. Block 0 1 2 3 4 5 6 7 8 9 10 11 12 13 BOT D S S S S S D D D F D D D EOD Position A B C D If the Block Address Type (BT) bit is set in the CDB when the LOCATE command is issued, all the setmarks and/or filemarks are logically grouped with its nearest Data Block on its BOT side to form one logical block.
Commands: Locate (2Bh) Page 49 Completion Status The Completion Status for the LOCATE command is shown in the following table. Code Message 00h Good Status 02h Check Condition Description • • • The tape is positioned to the logical block address specified. The drive remains in any previously set mode. The drive is ready to perform any appropriate command. Extended Sense Byte 02h: Code Message Description 02h 04h Not Ready Hardware Error No cartridge is inserted in the drive.
Page 50 DDS-4 SCSI Interface Manual, Rev. B LOG SELECT (4Ch) The LOG SELECT and LOG SENSE commands are used in conjunction with each other. These commands allow the host to obtain and control statistical information about cartridge usage and error rates. This information consists of counts related to particular events that occur. Count thresholds can be established which automatically generate log exception conditions.
Commands: Log Select (4Ch) Page 51 Command Descriptor Block Field Description The following table defines the fields in the CDB. Field Name Bytes Bits Description PCR bit 1 1 The Parameter Code Reset (PCR) bit is used to reset log parameters. If the bit is set (1) and the parameter list length is set to 0, all accumulated values are set to 0. All threshold values are set to the defaults. Pages 0, 30, and 31 are not reset with this bit. When the PCR bit is set, the PC bits in the CDB are ignored.
Page 52 DDS-4 SCSI Interface Manual, Rev. B The drive presets the values as follows: • The default accumulated values are set to all 0s. • The default threshold values are set to all 1s. The default values cannot be changed. If the host issues a LOG SELECT command with the PC bit specifying default values when the parameter list length is nonzero, a Check Condition is returned. The sense data is set to Illegal Request, Invalid Field in the CDB.
Commands: Log Select (4Ch) Page 53 • Correct determination of the pages the drive uses. • Determination of the parameter codes and length of each parameter. The drive does not maintain a separate set of log parameters for each initiator. Therefore, a LOG SELECT command affects all initiators. Note: The subsequent section discusses the LOG SENSE command. The log page codes and the log parameter codes are described in that section. Parameter data is made up of one or more page descriptors.
Page 54 DDS-4 SCSI Interface Manual, Rev. B • If any page headers are received with unsupported page codes. (Table 4-30 lists the pages that can be set by the LOG SELECT command.) • An incorrect log page length is specified in the page header. • An illegal parameter code within a valid log page. • Valid log pages are not sent in ascending order. • Parameter codes of a supported page are not sent in ascending order. The following table shows the log page header format.
Commands: Log Select (4Ch) Page 55 issued to specify the control bytes for the threshold parameter, the accumulated Parameter Control byte is affected. The LOG SENSE data reflects the current setting of the control byte for the parameter. The Parameter Control byte bits used by the drive are described in the following table. Bit Name Bytes Bits Description Disable Update (DU) 2 7 When set (1), this bit indicates that the host does not want this counter to be updated.
Page 56 DDS-4 SCSI Interface Manual, Rev. B set to Log Exception; and the additional sense code qualifier is set to Threshold Condition Met, 5B/01. If the counter is disabled because the DU bit is set (1), no threshold conditions are compared because the counter will not be incremented.
Commands: Log Sense (4Dh) Page 57 LOG SENSE (4Dh) The LOG SELECT and LOG SENSE commands are used in conjunction with each other. These commands allow the host to obtain and control statistical information. This information consists of counts related to particular events that occur.
Page 58 DDS-4 SCSI Interface Manual, Rev. B Command Descriptor Block Field Description The following table defines the fields in the CDB. Field Name Bytes Bits Description PC bits 2 6-7 These Page Control bits select one of four possible types of log information. These bit settings are shown in Using Page Control Bits. Page Code 2 0-5 This field indicates the requested page code.
Commands: Log Sense (4Dh) Page 59 Using Page Control Bits The Page Control (PC) bits specify the type of counts that the initiator is requesting. For page 0, the PC bits are ignored. For other pages, the PC bits specify the type of parameter values. The following table lists the Page Control bit values.
Page 60 DDS-4 SCSI Interface Manual, Rev. B command. The default threshold values are loaded into the threshold values when a reset occurs or by a LOG SELECT command with the PCR bit set. Default Accumulated Values The type 3 page control bit setting specifies default accumulated values. The default accumulated values are all zero and cannot be changed by the LOG SELECT command.
Commands: Log Sense (4Dh) Page 61 The following subsections describe the log sense pages. List of Available Pages (Page 0) Page 0 indicates the log sense pages used by the drive. To determine the size of each page and of each parameter in the page, the individual pages must be requested. Page 0 is unique in that the parameter data returned does not contain log parameter headers. All other pages return a page header followed by zero or more variablelength log parameters.
Page 62 DDS-4 SCSI Interface Manual, Rev. B Bits Byte 7 6 5 4 0 3 2 1 0 MSB—Parameter Code 1 Parameter Code—LSB 2 Parameter Control 3 Parameter Length (n-3) 4 Parameter Value N Parameter Value The Parameter Code field identifies the log parameter being returned to the initiator. If the Parameter Pointer field of the CDB is zero, the parameter code of the first log parameter indicates the first parameter code supported by the drive for this log page.
Commands: Log Sense (4Dh) Page 63 0004 2 Not applicable (always returns 0) 0005 8 Total bytes processed (written) 0006 2 Total uncorrectable errors 8007 2 Rewrites since last read-type operation The total rewrite count is incremented each time a frame sequence is rewritten on tape. Rewrites are used to recover from media errors detected by the RAW (readafter-write) checking feature of the drive. The total errors corrected count is the same as the total rewrite count.
Page 64 DDS-4 SCSI Interface Manual, Rev. B The total errors corrected count is incremented each time the drive recovers from a read error. This count includes the reread count and all C3 ECC errors that could be corrected. Note: This count does NOT include any frames read that were rewritten when the tape was recorded. The total correctable ECC error count is incremented each time the ECC process corrects one to two erroneous tracks read from the tape.
Commands: Log Sense (4Dh) Page 65 Additional information regarding the Tape Alert system is found in the SCSI-3 Stream Commands (SSC) Standard.
Page 66 DDS-4 SCSI Interface Manual, Rev. B The format of the Tape Alert Log Page is shown below: Bits Byte 7 6 5 4 1 0 0 0 0 2 MSB 3 LSB 3 2 1 0 0 0 0 0 LBIN(0) LP(0) 0 Page Length (140h) 5n-1 MSB – Parameter Code 5n 5n+1 LSB – Parameter Code DU(0) DS(1) TSD(0) ETC(0) TMC 5n+2 Parameter Length (1) 5n+3 Value of Flag (set when bit 0 = 1) There are 64 Tape Alert flags for drives and autoloaders, (some are reserved).
Commands: Log Sense (4Dh) Page 67 No Flag Type Required Host Message Cause 14 Unrecoverable Snapped Tape C The operation has failed because the tape in the drive has snapped: Tape snapped/cut in the drive where media cannot be ejected 16 Forced Eject C The operation has failed because the tape cartridge was manually ejected while the tape drive was actively writing or reading.
Page 68 DDS-4 SCSI Interface Manual, Rev. B The following table lists the flags supported by the autoloader: No. Flag Type Required Host Message Cause 40 Loader Hardware A C The changer mechanism is having difficulty communicating with the tape drive: Loader mechanism is having trouble communicating with the tape drive 1. Turn the autoloader off then on. 2. Restart the operation. 3. If problem persists, call the tape drive supplier helpline.
Commands: Log Sense (4Dh) Page 69 When a previously used cartridge is inserted, the total counts are updated to the values contained in the Tape Log of the inserted cassette. The total counts can be read with the LOG SENSE command. Also, page 30 contains a set of current counts. The current usage counts are not part of the Tape Log. They are initialized to 0 when the cartridge is inserted.
Page 70 DDS-4 SCSI Interface Manual, Rev. B Name Code Length Previous ECC C3 Corrections 0008 2 This count is the number of times the drive used C3 ECC correction to recover data from the partition during the last cartridge usage cycle. Description Total Groups Written 0009 4 This count is the number of groups written since the partition was formatted. This count accumulates over the life of the cartridge but is zeroed if the tape is formatted again.
Commands: Log Sense (4Dh) Page 71 Data Compression Transfer Log Page (Page 39) Page 39, the Data Compression Transfer Log Page, allows you to monitor the performance of data compression.
Page 72 DDS-4 SCSI Interface Manual, Rev. B Parameter Code Length Name 07 08 3 3 Minutes since last cleaning Power on time (minutes) 09 3 Cylinder on time (minutes) 0A 2 Cleaning Cartridge count 0B 2 Reserved 0C 2 Reserved 0D 2 Reserved 0E 2 Reserved 0F 2 Reserved 10 2 Reserved 11 1 Reserved 12 1 Reserved Completion Status The Completion Status for the LOG SENSE command is shown in the following table.
Commands: Mode Select (15h) Page 73 MODE SELECT (15h) The MODE SELECT command allows the host to assign device parameters. After a power-on or SCSI reset condition, the drive sets its device parameters to the default values. By issuing a MODE SELECT command, the host can change the device parameters. The parameters are transferred to the drive as data formatted in a parameter list.
Page 74 DDS-4 SCSI Interface Manual, Rev. B Command Descriptor Block Field Description The following table defines the fields in the CDB. Field Name Bytes Bits Description PF bit 1 4 The Page Format (PF) bit indicates whether the drive should interpret the MODE SELECT parameters that follow the CDB and the header as SCSI-1 or as SCSI-2 parameters. For the Scorpion 40 drives, the PF bit must be set to 1 (SCSI-2).
Commands: Mode Select (15h) Page 75 Parameter List Header Field Descriptions The following table defines the fields in the Parameter List Header. Field Name Buffered Mode Bytes Bits 2 6-4 Description This field sets the buffering mode of the drive The default mode is 001, buffered, The drive may report good status on write commands as soon as all the data specified in the write command has been transferred to the drive’s buffer.
Page 76 DDS-4 SCSI Interface Manual, Rev. B Parameter List—Block Descriptor Field Descriptions The following table defines the fields in the Parameter List block descriptor. Field Name Density Code Bytes Description 0 The following values define this field: Hex Code Meaning 00 Default format (DDS) 7F No-op 25 DDS-3 26 DDS-4 47 DAT 72 The drive will accept any of these density codes as valid when sending a Block Descriptor.
Commands: Mode Select (15h) Page 77 The following table explains the page layout fields Field Name Page Code Bytes Description 0 The Page Code field identifies the format and parameters for this page as follows: Hex Code Page Name 02 Disconnect/reconnect 0A Control mode 0F Data compression control 10 Device configuration 11 Medium partition 1C 1D Tape Alert Mode Element address assignment (Autoloader only) Device capabilities (Autoloader only) 1F Page Length 1 The Page Length field specifies the l
Page 78 DDS-4 SCSI Interface Manual, Rev. B Disconnect/Reconnect Page Field Descriptions The following table describes the fields in the Disconnect/Reconnect page. Field Name Bytes Bits Description Page Code 0 The Page Code field must be set to 02h to select this page. Page Length 1 The Page Length field must be set to 14 (0Eh), which indicates that 14 parameter bytes follow the Page Length byte.
Commands: Mode Select (15h) Page 79 Control Mode Page Field Descriptions The following table describes the fields in the Control Mode page. Field Name Bytes Bits Description Page Code 0 0-5 Page Length 1 Report Log Exception Condition 2 0 A Report Log Exception Condition (RLEC) bit of 1 specifies that the target reports log exception conditions. Disable Queuing 3 0 The Disable Queuing bit must be 1 to signify that tagged queuing is disabled.
Page 80 DDS-4 SCSI Interface Manual, Rev. B DC Control Page Field Descriptions The following table describes the fields in the DC Control page. Field Name Bytes Bits Description DCC 2 6 The DCC (Data Compression Capable) bit indicates that the drive is capable of data compression. This bit is always 1. Note that data control compression may be disabled by the switches on the drive. DCE 2 7 The DCE (Data Compression Enable) bit controls data compression.
Commands: Mode Select (15h) 0 Page 81 0 0 | Page Code (10h) 1 2 Page Length (0Eh) 0 CAP CAF DIS RAW EN C3 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 3 N-Group Active Partition 6 MSB—Write Delay Time 7 Write Delay Time—LSB 8 0 BIS RSMK 0 0 0 0 REW 9 0 0 0 0 0 0 0 0 10 0 0 0 EEG SEW 0 0 0 11 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0
Page 82 DDS-4 SCSI Interface Manual, Rev. B Device Configuration Page Field Descriptions The following table describes the fields in the Device Configuration page. Field Name Bytes Bits Description Page Code 0 0-5 Page Length 1 CAP bit 2 6 The CAP (Change Active Partition) bit is used to effect a partition change. When the CAP bit is 1, the drive switches to the partition specified in the Active Partition field.
Commands: Mode Select (15h) Page 83 Field Name Bytes Bits Description REW bit 8 0 The default value for the REW bit is 0. The Report Early Warning (REW) bit determines whether or not the drive reports an early-warning condition on a read operation. The effect of this bit is different for read and write operations. For read-type operations, if this bit is 0, the drive does not report the early-warning condition.
Page 84 DDS-4 SCSI Interface Manual, Rev. B Medium Partition Page Field Descriptions The following table describes the fields in the Medium Partition page. Field Name Bytes Bits Description Page Code 0 0-5 The Page Code field must be set to 11h to select this page.
Commands: Mode Select (15h) Page 85 Tape Alert Mode Page 1C Bits Byte 7 6 5 4 0 0 0 Page Code (1Ch) 1 Page Length (0Ah) 2 Perf 3 Reserved 4 Interval Timer (MSB) 5 Interval Timer 6 Interval Timer 7 Interval Timer (LSB) 8 Report Count/Test Flag Number (MSB) 9 Report Count/Test Flag Number 10 Report Count/Test Flag Number 11 Report Count/Test Flag Number (LSB) Reserved 3 2 1 0 DExcpt Test Reserved LogErr MRIE DExcpt (Default set to 1): When this bit is set to zero the
Page 86 DDS-4 SCSI Interface Manual, Rev. B Test and DExcpt bits are set to one and Test Flag Number set to zero, then the MODE SELECT command will return Check Condition, with sense key set to Illegal Request and extended sense set to Invalid Field in Parameter List. When the Test bit is set to one and the Test Flag Number is set to valid non-zero value, the drive will generate/clear a test informational exception condition. The value of the Test bit returned by a Mode Sense command will remain at zero.
Commands: Mode Select (15h) Page 87 (which is 5D00h for a Tape Alert event). The command that has the Check Condition shall complete without error before any exception condition may be reported (and thus does NOT need to be repeated). 0x4: Unconditionally generate Recovered Error.
Page 88 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the MODE SELECT command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The defined mode is set and remains set until another MODE SELECT or RESET command is issued. • The tape position is not changed.
Commands: Mode Sense (1Ah) Page 89 MODE SENSE (1Ah) The MODE SENSE command allows the host to determine various drive device parameters. These parameters are sent from the drive to the host as data formatted in a parameter list. This command is a complementary command to the MODE SELECT command.
Page 90 DDS-4 SCSI Interface Manual, Rev. B Command Descriptor Block Field Description The following table defines the fields in the CDB. Field Name Bytes Bits Description DBD bit 1 3 If the Disable Block Descriptors (DBD) bit is set to 0, the drive always returns the block descriptor in the MODE SENSE data. If the DBD bit is set to 1, the drive does not return the block descriptor in the MODE SENSE data. NOTE: When the DBD is 1, the Block Descriptor Length in the parameter header is set to 0.
Commands: Mode Sense (1Ah) Page 91 MODE SENSE Parameters The parameter list for the MODE SENSE command contains • A four-byte header, followed by • Zero or one eight-byte Block Descriptor, followed by • Zero or more variable-length pages. The following table illustrates the structure of the Mode Sense command. Byte Bits 7 6 5 4 0 . . 3 3 2 1 0 Parameter List Header 4 . . 11 Block Descriptor 12 . . .
Page 92 DDS-4 SCSI Interface Manual, Rev. B Field Name Bytes Bits 3 Block Descriptor Length Description This field indicates the number of bytes of block descriptor information that follow the parameter header. If the DBD bit is set to 1, the block descriptor length is set to 0 (00h), which indicates that no block descriptor is returned in the MODE SENSE data. If the DBD bit is set to 0, the block descriptor length is set to 8 (08h), indicating that an eight-byte block descriptor is returned.
Commands: Mode Sense (1Ah) Density Page 93 The values for the Density Code field are as follows: 25h DDS-3 format 26h DDS-4 format 0 Code 47h DAT-72 NOTE: Although the above values are approved by the ANSI X3T9 Technical Committee, the values are not published in the SCSI-2 standard. Block This field indicates the size of a fixed-length logical block. Byte 5 is the MostSignificant-Byte (MSB); byte 7 is the Least-Significant-Byte (LSB). The default fixed-block size for the drive is 512 bytes (200h).
Page 94 DDS-4 SCSI Interface Manual, Rev. B Disconnect/Reconnect Page (02h) The Disconnect/Reconnect page allows the host to tune performance of the SCSI bus. The following table illustrates this page.
Commands: Mode Sense (1Ah) Page 95 Control Mode Page (0Ah) The Control Mode page allows the host to enable or disable the generation of a Check Condition when log parameters whose ETC bits are set to 1 meet their Threshold Condition. (Refer to the LOG SELECT command and the LOG SENSE command.) The layout of this page is shown in the following table.
Page 96 DDS-4 SCSI Interface Manual, Rev. B Bits Byte 7 6 5 4 3 2 8 Decompression Algorithm 9 Decompression Algorithm 10 Decompression Algorithm 11 Decompression Algorithm 1 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 0 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 DC Control Page Field Descriptions The following table describes the fields in the DC Control page.
Commands: Mode Sense (1Ah) 01-1F 21-FF Page 97 The data last sent to the host was compressed using an algorithm other than the DCLZ algorithm. The contents of the DDS-DC entity header algorithm byte are returned. Device Configuration Page (10h) The Device Configuration page specifies the appropriate sequential access device configuration. The following table illustrates this page.
Page 98 DDS-4 SCSI Interface Manual, Rev. B Device Configuration Page Field Descriptions The following table describes the fields in the Device Configuration page. Field Name Bytes Bits Description Page Code 0 0-5 The Page Code field must be set to 10h to select this page. Page Length 1 DIS RAW 2 4 The DIS RAW (Disable Read-After Write) bit enables and disables the read-after write capability. If the value is 1, read-after-write check and rewrites are disabled.
Commands: Mode Sense (1Ah) Page 99 Medium Partition Page (11h) The Medium Partition page indicates single- or dual-partition tape format. the MODE SENSE command specifying a Medium Partition page can be executed at any logical position. The tape does not need to be positioned at BOM. The layout of this page is shown in the following table.
Page 100 DDS-4 SCSI Interface Manual, Rev. B Element Address Assignment Page (Autoloader Only—1Dh) The data in the Element Address Assignment page informs the host of which type of elements and how many elements of each type are supported by the current configuration of the Autoloader (as defined in the EXCHANGE MEDIUM COMMAND drive). The following table shows the layout of this page.
Commands: Mode Sense (1Ah) Page 101 Bits Byte 7 6 5 4 3 2 1 0 10 0 0 0 0 0 0 0 0 11 0 0 0 0 0 0 0 0 12 0 0 0 0 0 0 0 0 13 0 0 0 0 1 0 0 0 14 0 0 0 0 0 0 0 0 15 0 0 0 0 0 0 0 0 16 0 0 0 0 0 0 0 0 17 0 0 0 0 0 0 0 0 18 0 0 0 0 0 0 0 0 19 0 0 0 0 0 0 0 0 The data in the Device Capabilities Page informs the initiator of the following: • A cartridge can be stored in the data transfer and storage elements.
Page 102 DDS-4 SCSI Interface Manual, Rev. B MOVE MEDIUM (Autoloader only) (A5h) The MOVE MEDIUM command requests that the Autoloader move a cartridge form a source element to a destination element. The drive must be either the source or destination element. MOVE MEDIUM Command Descriptor Block The following table shows the layout of the CDB.
Commands: Move Medium (A5h) Page 103 Completion Status The Completion Status for the MOVE MEDIUM command is shown in the following table. Code Message Description 00h Good Status • The drive is ready for another command. • The cartridge has been moved to the specified location. If the cartridge was moved to the drive, it is positioned at BOT. 02h Check Condition Extended Sense Byte 02h: Code Message Description 02h Not Ready No magazine present.
Page 104 DDS-4 SCSI Interface Manual, Rev. B PREVENT/ALLOW MEDIA REMOVAL (1Eh) If the Prevent/Allow Media Removal command is sent, the cartridge cannot be ejected using the Eject button on the front of the drive. After a Reset, the default state of the drive is in the ALLOW command mode. An UNLOAD command ejects the cartridge even after a PREVENT command. PREVENT/ALLOW MEDIA REMOVAL Command Descriptor Block The following table shows the layout of the CDB.
Commands: Read (08h) Page 105 READ (08h) The READ command transfers one or more bytes or blocks from the drive to the Initiator beginning with the next logical block on tape. READ Command Descriptor Block The following table shows the layout of the CDB.
Page 106 DDS-4 SCSI Interface Manual, Rev. B Description of the READ Command The READ command is complete when one of the following conditions is met. These conditions are described in the following paragraphs. • End-of-Data (EOD) is reached. • A filemark (FM) is read. • Transfer length is satisfied • End-of-Tape (EOT) or end-of-partition (EOP) is reached. • Unrecoverable data error occurs. • Detection of incorrect block length.
Commands: Read (08h) Page 107 Transfer Length Satisfied If the CDB Transfer Length is satisfied, the command completes successfully with a Good Status, and the tape is positioned on the EOT side of the last block read. End of Tape (EOT) or End-of-Partition (EOP) When the end-of-tape or end-of-partition position is encountered, the command terminates with a Check Condition and Medium Error (03h) sense key. The Valid bit (byte 0, bit 7) and the EOM bit (byte 2, bit 6) are set.
Page 108 DDS-4 SCSI Interface Manual, Rev. B • If the actual block length exceeds the CDB Transfer Length, the Incorrect Length error is reported. • If the actual block length is smaller than the CDB Transfer Length and the SILI bit is 1, the drive ignores (that is, suppresses) the Incorrect Length error. • If the actual block length is different than the CDB Transfer Length and the SILI bit is 0, the drive reports the Incorrect Length error.
Commands: Read (08h) Page 109 For example, assume the following: • The drive is currently positioned before block N. • Block N + 1 contains 512 bytes. The host issues a READ command with a CDB Transfer Length of 514, indicating 514 bytes of data to be read. The drive transfers the first 512 bytes of block N; then stops because of an Incorrect Length error. The logical position after the error is after byte 512 of block N.
Page 110 DDS-4 SCSI Interface Manual, Rev. B READ BLOCK LIMITS (05h) The READ BLOCK LIMITS command causes the drive to transfer the block length limits to the Initiator. The minimum block length is 1 byte; the maximum is 224-1 bytes. The minimum and maximum block limits are returned to the Initiator in a sixbyte data string. READ BLOCK LIMITS Command Descriptor Block The following table shows the layout of the CDB.
Commands: Read Block Limits (05h) Page 111 Completion Status The Completion Status for the READ BLOCK LIMITS command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The drive remains in any previously set mode. • The tape position is not changed. 02h Check Condition Extended Sense Byte 02h: Code Message Description 02h 04h 05h Not Ready Hardware Error Illegal Request No cartridge is inserted in the drive.
Page 112 DDS-4 SCSI Interface Manual, Rev. B READ DATA BUFFER (3Ch) The READ DATA BUFFER command returns the 4-byte Read Buffer header plus the number of bytes specified by the allocation Length field. This command is used in conjunction with the WRITE DATA BUFFER command as a diagnostic function for testing the drive buffer memory and confirming the SCSI bus integrity. The tape is not accessed during execution of this command.
Commands: Read Data Buffer (3Ch) Page 113 READ DATA BUFFER Header The following table shows the header layout for the READ DATA BUFFER command. Bits Byte 7 6 5 4 3 2 1 0 0 0 0 0 0 0 0 0 0 1 MSB—Available length 2 Available length 3 Available length READ DATA BUFFER Header Field Descriptions The READ BUFFER header contains four bytes. • The first byte is reserved and set to zero. • Bytes one, two and three contain the capacity of the space available in the drive buffer.
Page 114 DDS-4 SCSI Interface Manual, Rev. B READ ELEMENT STATUS (Autoloader Only) (B8h) The READ ELEMENT STATUS command requests the Autoloader to report the status of its elements to the host. The status of ALL element types are reported. READ ELEMENT STATUS Command Descriptor Block The following table shows the layout of the CDB.
Commands: Read Element Status (B8h) Page 115 The following example illustrates the data structure returned for a 12-slot magazine. Element Status Data (8-byte header) Medium Transport Element (changer) Page (8-byte header) Medium Transport element Descriptor (12 bytes) Storage element Page (8-byte header) Storage Element Descriptors (12 bytes each; for a six-slot magazine=72 bytes) . . .
Page 116 DDS-4 SCSI Interface Manual, Rev. B Bits Byte 7 6 5 4 0 1 0 0 0 2 2 1 0 0 0 0 0 0 0 0 MSB Element Descriptor Length 3 4 3 Element Type Code LSB Element Descriptor Length 0 0 5 0 0 0 0 MSB—Byte Count of Descriptor Available 6 Byte Count of Descriptor Available 7 Byte Count of Descriptor Available—LSB 8 Element Descriptor . . . n Element Descriptor The element type code field indicates the element type reported in this field.
Commands: Read Element Status (B8h) Page 117 Storage Element Descriptor The 12-byte storage element descriptor is returned (within the CDB request) for each cartridge slot in the magazine (six). The following table shows the storage element descriptor.
Page 118 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the READ ELEMENT STATUS command is shown in the following table. Code Message Description 00h Good Status • The drive is ready for another command. Check Condition Extended Sense Byte 02h: 02h • All the status data has been sent. Code Message Description 04h 05h Hardware Error Illegal Request • 06h Unit Attention Drive hardware failure detected.
Commands: Read Position (34h) Page 119 READ POSITION (34h) The READ POSITION command reports the block address of the current logical block. The current logical block is the first logical block that would be read from the current tape partition if a READ command were issued. READ POSITION Command Descriptor Block The following table shows the layout of the CDB.
Page 120 DDS-4 SCSI Interface Manual, Rev. B READ POSITION Data Format The following table shows the layout for the READ POSITION data format when the Long and TCLP bits are set to 0.
Commands: Read Position (34h) Last Block Location Page 121 8-11 These fields indicate the block address associated with the current logical position. The value indicates the block address of the next data block to be transferred between the Initiator and the drive if a READ or WRITE command is issued. Block 0 is the first block on each partition. READ POSITION Data Format The following table shows the layout for the READ POSITION data format when the Long and TCLP bits are set to 1.
Page 122 DDS-4 SCSI Interface Manual, Rev. B Field Name Bytes Bits BOP bit 0 7 Description 0 = The current logical position is not at BOT. 1 = The current logical position is at Beginning-of-Partition (BOT). EOP bit 0 6 0 = The current logical position is not between early-warning and endof-tape. 1 = The current logical position is between early-warning and end-oftape. MPU 0 3 0 = File Number field is valid. 1 = File Number field is invalid. BPU 0 2 0 = Block Number field is valid.
Commands: Read Position (34h) Page 123 Completion Status The Completion Status for the READ POSITION command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The drive remains in any previously set mode. • The tape is not moved. 02h Check Condition Extended Sense Byte 02h: Code Message Description 02h Not Ready No cartridge is inserted in the drive.
Page 124 DDS-4 SCSI Interface Manual, Rev. B RECEIVE DIAGNOSTIC RESULTS (1Ch) The RECEIVE DIAGNOSTIC RESULTS command requests any available analysis data is sent to the initiator after completion of a SEND DIAGNOSTIC command. The drive does not use any of the optional diagnostic page data; thus, no data is returned with this command. RECEIVE DIAGNOSTIC RESULTS Command Descriptor Block The following table shows the layout of the CDB.
Commands: Receive Diagnostic Results (1Ch) Page 125 occurred during one of the tests, byte 4 is set to the previous test that passed successfully. If no errors occurred during the Enhanced Diagnostics or the Enhanced Diagnostics were not invoked, the Error code field (byte 5) is set to 0. If an error occurred during the testing, byte 5 will contain the Vendor-specific Code Qualifier, the meaning of which is defined in the Request Sense Command.
Page 126 DDS-4 SCSI Interface Manual, Rev. B RELEASE UNIT (17h / 57h) The RELEASE UNIT command releases a current drive reservation, if the command is received form the Initiator that originally established the reservation. If the original reservation was made for a third party, the RELEASE UNIT command Descriptor Block must also carry the third party data.
Commands: Report Density Support (44h) Page 127 10-byte version: Bits Byte 7 6 5 4 3 2 1 0 0 0 1 0 1 0 1 1 1 1 0 0 0 3rd Pty 0 0 LongID* 0 2 0 0 0 0 0 0 0 0 4 0 0 0 0 0 0 0 0 5 0 0 0 0 0 0 0 0 6 0 0 0 0 0 0 0 0 Flag Link 3 Third-Party Device ID 7 Parameter List Length (MSB)* 8 Parameter List Length (LSB)* 9 vendor unique* 0 0 0 0 * These fields must be set to zero.
Page 128 DDS-4 SCSI Interface Manual, Rev. B REPORT DENSITY SUPPORT (44h) The REPORT DENSITY SUPPORT command requests transfer of information regarding the supported densities for the logical unit to the host. REPORT DENSITY SUPPORT Command Descriptor Block The following table shows the layout of the CDB for REPORT DENSITY SUPPORT.
Commands: Report Density Support (44h) Page 129 REPORT DENSITY SUPPORT Header The following table shows the header layout for the REPORT DENSITY SUPPORT command. Bits Byte 7 6 0-1 5 4 3 2 1 0 Available density support length 2 Reserved 3 Reserved The AVAILABLE DENSITY SUPPORT LENGTH field specifies the number of bytes in the following data that are available to be transferred. The available density support length does not include itself.
Page 130 DDS-4 SCSI Interface Manual, Rev. B Field Name Bytes Bits per MM 5-7 Bits Description Bits per millimeter per track. Value depends on density code DDS3-DDS4 – 12C0h DAT 72 – 1838h Media width 8-9 Media width in tenths of millimeters. Specification width is 3.8 mm, this value is 26h Tracks 10-11 Tracks on a helical scan drive are defined as 1.
Commands: Request Block Address (02h) Page 131 REQUEST BLOCK ADDRESS (02h) The REQUEST BLOCK ADDRESS command requests the drive to transfer the current block address to the Initiator. This command returns the block address number on tape. REQUEST BLOCK ADDRESS Command Descriptor Block The following table shows the layout of the CDB.
Page 132 DDS-4 SCSI Interface Manual, Rev. B REQUEST BLOCK ADDRESS Address Data Field Description The Block Address Fields (bytes 0 through 2) report the current tape position block number. The first block on the tape is block number one. Thus the Block Address returned will range from one to the maximum block currently written. Completion Status The Completion Status for the REQUEST BLOCK ADDRESS command is shown in the following table.
Commands: Request Sense (03h) Page 133 REQUEST SENSE (03h) The REQUEST SENSE command causes the drive to transfer status data to the Initiator pertaining to the last command. REQUEST SENSE Command Descriptor Block The following table shows the layout of the CDB.
Page 134 DDS-4 SCSI Interface Manual, Rev. B Bits Byte 7 6 5 4 3 15 SKSV C/D 0 0 BPV 2 | 16 MSB—Field Pointer 17 Field Pointer—LSB 1 0 Bit Pointer Sense Data Field Descriptions The Sense Data field descriptions are shown in the following table. Field Name Bytes Bits Description Valid bit 0 7 The Valid Bit indicates that the Information field (Bytes 3 to 6) contains a valid residual length.
Commands: Request Sense (03h) Page 135 Field Name Bytes Field Pointer 16-17 Bits Description If the BPV bit is set, this field points to the most significant byte of the field in error. Bytes are numbered starting from 0. When a Log Exception is generated, bytes 16 and 17 indicate the MSB and LSB of the Log Parameter code that caused the Log Exception. Byte 15 indicates the affected page that caused the Log Exception.
Page 136 DDS-4 SCSI Interface Manual, Rev. B The following table lists the additional sense code and code qualifiers.
Commands: Request Sense (03h) Page 137 Byte 2 (Sense Key) Byte 12 (ASC) Byte 13 (ASCQ) Definition (Additional sense code) 3 30 C4 Block Access Table corruption during reading 3 31 00 Medium format corrupted 3 3B 00 Sequential positioning error 3 3B 01 Tape position error at beginning of medium 3 3B 02 Tape position error at end of medium Reposition error 3 3B 08 3 3B BF Tape position error with head clog 3 50 00 Write append error 3 50 01 Write append position error
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Commands: Request Sense (03h) Page 139 Byte 2 (Sense Key) Byte 12 (ASC) Byte 13 (ASCQ) Definition (Additional sense code) 4 44 D3 AIC internal read parity error 4 44 D4 Microprocessor Cache Failure 4 44 D5 EEPROM failure 4 44 E0 Loader clamp failure 4 44 E1 Loader cassette arm failure 4 44 E2 Loader error LCP failure 4 44 E3 Loader hardware failure 4 51 00 Erase failure 4 53 00 Media load or eject failure 4 53 01 Unload tape failure 1A 00 Parameter list length
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Commands: Request Sense (03h) Page 141 Bytes 16-17 Definition (vendor-unique SKSV codes) 1B Diagnostic DMA write RD parity error 1C Diagnostic DMA write micro port access error 1D Diagnostic DMA write counter error 1E Diagnostic DMA write data compare error 1F Diagnostic DMA read interrupt failed 20 Diagnostic DMA read FIFO overrun 21 Diagnostic DMA read offset error 22 Diagnostic DMA read HI parity error 23 Diagnostic DMA read RD parity error 24 Diagnostic DMA read micro port access
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Commands: Request Sense (03h) Bytes 16-17 Page 143 Definition (vendor-unique SKSV codes) 86 Invalid entity compression algorithm 87 Invalid entity record length field 88 Invalid entity record count field 89 Group buffer configuration error 8A Host buffer configuration error 8B Invalid ring buffer descriptor 8C Invalid BAT entry 8D Invalid BAT sequence found 8E Invalid cassette data format ID 8F Transfer skip BAT entry missing 90 Unrecoverable ECC error 91 Encountered a DCLZ error
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Commands: Request Sense (03h) Page 145 Bytes 16-17 Definition (vendor-unique SKSV codes) EB Tape cassette load error EC Tape cassette unload error ED Tape capstan error EE Tape cylinder error EF Tape reel error F0 Tape mechanical error F1 Tape cut F2 Tape jam F3 Write append positioning error F4 Internal tape reader error F5 Tape audio format F6 Tape write append error F7 Tape is not initialized F8 Emergency eject F9 Internal tape process error FA Initialize failed FB Er
Page 146 DDS-4 SCSI Interface Manual, Rev. B RESERVE UNIT (16h / 56h) The RESERVE UNIT command reserves the drive for exclusive use of the requesting Initiator or for the exclusive use of third party specified SCSI device. Note: The 6-byte version of the RESERVE UNIT command uses opcode 16h; the 10-byte version uses opcode 56h.
Commands: Reserve Unit (16h / 56h) Page 147 10-byte version The drive also supports the SCSI-3 10-byte Reserve Unit Command. The table below shows the descriptor block for the 10-byte CDB.
Page 148 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the RESERVE UNIT command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The drive remains in any previously set mode. • The drive is reserved for the use of the specified ID. • The tape position is not changed.
Commands: Rewind (01h) Page 149 REWIND (01h) The REWIND command causes the drive to rewind the cartridge to the Beginningof-Partition (BOP). Any write data remaining in the buffer will be first recorded to the tape, and an EOD marker will be recorded. The REWIND operation is done in the high speed mode. REWIND Command Descriptor Block The following table shows the layout of the CDB.
Page 150 DDS-4 SCSI Interface Manual, Rev. B SEEK BLOCK (0Ch) The SEEK BLOCK command is used to position the tape to the specified block address in the current partition. No data is transferred. SEEK BLOCK positions the tape to block locations greater or less than the current block position. Positioning is done with a high speed search and does not require a sequential read for the requested block.
Commands: Seek Block (0Ch) Page 151 Completion Status The Completion Status for the SEEK BLOCK command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The drive remains in any previously set mode. • The tape is positioned before the requested block. 02h Check Condition Extended Sense Byte 02h: Code Message 02h Not Ready Description No cartridge is inserted in the drive.
Page 152 DDS-4 SCSI Interface Manual, Rev. B SEND DIAGNOSTIC (1Dh) The SEND DIAGNOSTIC command requests the drive to perform diagnostic operations on itself. The diagnostic tests are part of the drive firmware and are more extensive than the power on self tests. Two tests are supported as defined in the CDB with bits 2-0 of byte 2. The self test does not require media and will not change any data on media in the drive.
Commands: Send Diagnostic (1Dh) Page 153 Completion Status The Completion Status for the SEND DIAGNOSTIC command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The drive remains in any previously set mode. • The tape position is not changed. 02h Check Condition Extended Sense Byte 02h: Code Message Description 02h Not Ready No cartridge is inserted in the drive.
Page 154 DDS-4 SCSI Interface Manual, Rev. B SPACE (11h) The SPACE command uses five methods to move the tape. This command moves the position: • Forward or backward a specified number of data blocks. • Forward or backward a specified number of filemarks. • Forward or backward a specified number of setmarks. • Forward a specified number of sequential (contiguously grouped) filemarks or setmarks. • Forward to the end of recorded data.
Commands: Space (11h) Page 155 Command Descriptor Block Field Descriptions The following table provides descriptions of the CDB fields.
Page 156 DDS-4 SCSI Interface Manual, Rev. B • If an unrecoverable data error is encountered, Check Condition is returned, Extended Sense Key is set to Medium Error, and Extended Sense Valid bit is set, indicating Residual Length is nonzero. Space by Position Functions The Count field is not applicable in space-to-EOD functions. In the space-to-EOD function, the tape is positioned such that a subsequent WRITE command appends data to the last recorded information on the tape.
Commands: Space (11h) Page 157 Referring to the first table, the table below shows the tape position after each SPACE command is complete. SPACE X Blocks From RSMK bit Tape Position 1 BOT ON B -7 EOD ON E 1 BOT OFF E -7 EPD OFF E 2 BOT ON C, chk cond res = 1 -8 EOD ON D, chk cond res = -1 2 BOT OFF F -8 EOD OFF A Completion Status The Completion Status for the SPACE command is shown in the following table.
Page 158 DDS-4 SCSI Interface Manual, Rev. B TEST UNIT READY (00h) The TEST UNIT READY command tests for three conditions: • The drive is powered on. • A cartridge is inserted in the drive. • The drive is ready to accept a medium-access command. If these three conditions are met, the drive returns Good Status. This command does not access the medium or initiate a diagnostic routine.
Commands: Test Unit Ready (00h) Page 159 If a cartridge is in the drive at power up and a TEST UNIT READY command is issued before the tape is positioned at BOT, then the following responses occur: First TUR Response Response during Tape Loading UNIT ATTN 29/00 NOT READY 04/03 If a cartridge is in the drive at power up and no TEST UNIT READY command is received until after the tape is positioned at BOT, then the following responses occur: First TUR Response Subsequent TUR Response UNIT ATTN 29/00 G
Page 160 DDS-4 SCSI Interface Manual, Rev. B VERIFY (13h) The VERIFY command verifies one or more blocks of data beginning with the next block from the tape unit. The command terminates after the specified number of bytes or blocks are verified or when the drive encounters a filemark, the EOT, or an unrecoverable error. On completion the medium is positioned after the last block verified or after a filemark.
Commands: Verify (13h) Page 161 The byte compare starts on a block boundary starting at the current tape block position. Completion Status The Completion Status for the VERIFY command is shown in the following table. Code Message Description 00h Good Status • The drive is ready to perform any appropriate command. • The drive remains in any previously set mode. • The tape is positioned on the EOT side of the last block verified.
Page 162 DDS-4 SCSI Interface Manual, Rev. B WRITE (0Ah) The WRITE command transfers one or more data blocks from the Initiator to the drive. If the Transfer Length is zero, no data is transferred, and the current position of the tape is not changed. This condition is not considered an error. WRITE Command Descriptor Block The following table shows the layout of the Command Descriptor Block.
Commands: Write (0Ah) Page 163 Code Message Description 00h Good Status • The SCSI data has been transferred to the data buffer. Check Condition Extended Sense Byte 02h: 02h • The drive remains in any previously set mode. Code Message 02h Not Ready Description No cartridge is inserted in the drive. 03h Media Error Unrecoverable data error encountered. Possibly bad cartridge. 04h 05h Hardware Error Illegal Request Drive hardware failure detected. The CDB contains an invalid bit.
Page 164 DDS-4 SCSI Interface Manual, Rev. B WRITE DATA BUFFER (3Bh) The WRITE DATA BUFFER command is used in conjunction with the READ DATA BUFFER command as a diagnostic function for testing the data buffer memory of the drive and confirming the SCSI bus integrity. The medium is not accessed during the execution of this command. The WRITE DATA BUFFER command can also be used to download the controller firmware if the drive is equipped with flash EEPROM.
Commands: Write Data Buffer (3Bh) Page 165 Command Descriptor Block Field Descriptions The following table provides descriptions of the CDB fields. Field Name Bytes Bits Description MODE 1 0-2 If MODE=0, only the data buffer is loaded. If MODE=2, data is loaded starting at the offset location specified by ADRS. If Mode=5, the data is transferred to the controller's flash EEPROM, and the firmware is restarted. For mode 4 and 5 the total transfer length must be A00000h with a starting offset of zero.
Page 166 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the WRITE DATA BUFFER command is shown in the following table. Code Message Description 00h Good Status • If Mode = 0, The Data Header is accepted and verified, if correct the data is accepted and written to the buffer at offset 0, the transfer length is the sum of the four byte header and the data to be written in the buffer. • If Mode = 2, the data is written to the buffer starting at the specified offset.
Commands: Write Filemarks (10h) Page 167 WRITE FILEMARKS (10h) The WRITE FILEMARKS command causes the specified number of filemarks or setmarks to be written to tape. This command can be used to force all remaining buffered data blocks to be written to tape without appending filemarks by specifying zero filemarks. When zero filemarks are specified, the command does not return Good Status to the Initiator until all buffered data blocks and filemarks are written correctly on the tape.
Page 168 DDS-4 SCSI Interface Manual, Rev. B Completion Status The Completion Status for the WRITE FILEMARKS command is shown in the following table. Code Message Description 00h Good Status • The filemarks have been sent to the buffer. Check Condition Extended Sense Byte 02h: 02h • The drive remains in any previously set mode. Code Message 02h Not Ready Description No cartridge is inserted in the drive. 03h Media Error Unrecoverable data error encountered. Possibly bad cartridge.
Commands: Write Filemarks (10h) Certance LLC 1650 Sunflower Avenue, Costa Mesa, California, 92626, USA Part Number 10010539-021; Printed in USA Page 169
