Hard Disk Drive Specifications Models: 2R015H1 & 2R010H1 P/N:1525/rev. A This publication could include technical inaccuracies or typographical errors. Changes are periodically made to the information herein – which will be incorporated in revised editions of the publication. Maxtor may make changes or improvements in the product(s) described in this publication at any time and without notice. Copyright © 2001 Maxtor Corporation. All rights reserved.
Before Y ou Begin You Thank you for your interest in Maxtor hard drives. This manual provides technical information for OEM engineers and systems integrators regarding the installation and use of Maxtor hard drives. Drive repair should be performed only at an authorized repair center. For repair information, contact the Maxtor Customer Service Center at 8002MAXTOR or 408-922-2085. Before unpacking the hard drive, please review Sections 1 through 4. CAUTION Maxtor hard drives are precision products.
Contents Section 1 — Introduction Maxtor Corporation Products Support Manual Organization Abbreviations Conventions Key Words Numbering Signal Conventions 1-1 1-1 1-1 1-1 1-1 1-2 1-2 1-2 1-2 Section 2 — Product Description Product Features Functional/Interface Zone Density Recording Read/Write Multiple Mode Ultra ATA - Mode 5 Multi-word DMA (EISA Type B) - Mode 2 Sector Address Translation Logical Block Addressing Defect Management Zone On-the-Fly Hardware Error Correction Code (ECC) Software ECC Correcti
Section 3 — Product Specifications Models and Capacities Drive Configuration Performance Specifications Physical Dimensions Power Requirements Power Mode Definitions Spin-up Seek Read/Write Idle Standby Sleep EPA Energy Star Compliance Environmental Limits Shock and Vibration Reliability Specifications Annual Return Rate Quality Acceptance Rate Start/Stop Cycles Data Reliability Component Design Life EMC/EMI EMC Compliance Canadian Emissions Statement Safety Regulatory Compliance 3-1 3-1 3-1 3-2 3-3 3-3 3-
Section 5 — AT Interface Description Interface Connector Pin Description Summary Pin Description Table PIO Timing DMA Timing Ultra DMA Timing Parameters 5-1 5-1 5-2 5-3 5-4 5-5 Section 6 — Host Software Interface Task File Registers Data Register Error Register Features Register Sector Count Register Sector Number Register Cylinder Number Registers Device/Head Register Status Register Command Register Read Commands Write Commands Mode Set/Check Commands Power Mode Commands Initialization Commands Seek, Fo
Write Verify Sector(s) Write Sector Buffer Write DMA Write Multiple Mode Set/Check Commands Set Features Mode Read Native Max Address Set Max Set Max Password Set Max Lock Set Max Unlock Set Max Freeze Lock Power Mode Commands Standby Immediate Idle Immediate Standby Idle Check Power Mode Set Sleep Mode Default Power-on Condition Initialization Commands Identify Drive Initialize Drive Parameters Seek, Format, and Diagnostic Commands S.M.A.R.T.
Figures Figure Title Page 2-1 3-1 4-1 4-2 4-3 4-4 5-1 5-2 5-3 5-4 5-5 5-6 5-7 5-8 5-9 5 - 10 5 - 11 5 - 12 5 - 13 PCBA Jumper Location and Configuration Outline and Mounting Dimensions Multi-pack Shipping Container Single-pack Shipping Container (Option A) Single-pack Shipping Container (Option B) IDE Interface and Power Cabling Detail Data Connector PIO Data Transfer to/from Device Multi-word DMA Data Transfer Initiating an Ultra DMA Data In Burst Sustained Ultra DMA Data In Burst Host Pausing an Ultra
INTRODUCTION SECTION 1 Introduction Maxtor Corporation Maxtor Corporation has been providing high-quality computer storage products since 1982. Along the way, we’ve seen many changes in data storage needs. Not long ago, only a handful of specific users needed more than a couple hundred megabytes of storage. Today, downloading from the Internet and CD-ROMs, multimedia, networking and advanced office applications are driving storage needs even higher.
INTRODUCTION Conventions If there is a conflict between text and tables, the table shall be accepted as being correct. Key Words The names of abbreviations, commands, fields and acronyms used as signal names are in all uppercase type (e.g., IDENTIFY DRIVE). Fields containing only one bit are usually referred to as the “name” bit instead of the “name” field. Names of drive registers begin with a capital letter (e.g., Cylinder High register).
PRODUCT DESCRIPTION SECTION 2 Product Description Maxtor hard disk drives are 3.5-inch diameter random access storage devices which incorporate an on-board Ultra ATA/100 controller. High capacity is achieved by a balanced combination of high areal recording density and the latest data encoding and servo techniques. Maxtor's latest advancements in electronic packaging and integration methods have lowered the drive's power consumption and increased its reliability.
PRODUCT DESCRIPTION Product Features Functional / Interface Maxtor hard drives contain all necessary mechanical and electronic parts to interpret control signals and commands from an AT-compatible host computer. See Section 3 Product Specifications, for complete drive specifications. Zone Density Recording The disk capacity is increased with bit density management – common with Zone Density Recording. Each disk surface is divided into 16 circumferential zones.
PRODUCT DESCRIPTION Defect Management Zone (DMZ) Each drive model has a fixed number of spare sectors per drive, all of which are located at the end of the drive. Upon detection of a bad sector that has been reassigned, the next sequential sector is used. For example, if sector 3 is flagged, data that would have been stored there is “pushed down” and recorded in sector 4. Sector 4 then effectively becomes sector 3, as sequential sectors are “pushed down” across the entire drive.
PRODUCT DESCRIPTION Major HDA Components Drive Mechanism A brush-less DC direct drive motor rotates the spindle at 5400 RPM (±0.1%). The dynamically balanced motor/spindle assembly ensures minimal mechanical run-out to the disks. A dynamic brake provides a fast stop to the spindle motor upon power removal. The speed tolerance includes motor performance and motor circuit tolerances.
PRODUCT DESCRIPTION Subsystem Configuration Dual Drive Support Two drives may be accessed via a common interface cable, using the same range of I/O addresses. The drives are jumpered as device 0 or 1 (Master/Slave), and are selected by the drive select bit in the Device/Head register of the task file. All Task File registers are written in parallel to both drives.
PRODUCT SPECIFICATIONS SECTION 3 Product Specifications Models and Capacities MODE L S Fo r matte d C ap acity 2R 015H 1 2R 010H 1 15.0 10.2 (GB yte LB A m o d e) M a xto r d efine s on e gi ga byte as 1 0E 9 or on e bi ll i on b y tes.
PRODUCT SPECIFICATIONS Physical Dimensions PARAM ETER Hei ght (m ax mm ) Wi dth ( typ i cal mm ) VALU E 17.5 101.6 Length (m ax mm ) 146.6 Weight (m ax kg ) 0.
PRODUCT SPECIFICATIONS Power Requirements M OD E 12V (ma) 5V (ma) 2050 350 -- Seek 260 350 6.0 Read/Wri te 260 350 5.4 Idle 190 250 4.0 Standby 30 125 1.4 Sleep 30 90 1.2 Spi n-up (peak) POW ER (w) Power Mode Definitions Spin-up The drive is spinning up following initial application of power and has not yet reached full speed. Seek A random access operation by the disk drive. Read/Write Data is being read from or written to the drive.
PRODUCT SPECIFICATIONS Shock and Vibration PARAM ETER OPER AT ING N ON-OPER AT ING Mechani cal Shoc k 30 Gs, 2.0 ms , no errors 300 Gs, 2.0 ms , no damage Rotational Shoc k Random Vi brati on Swept Sine Vi bration 10 to 300 Hz 20,000 Rad/sec ,0.5 to 1.0 ms , no d 10 to 45 Hz at 0.004 G2 /Hz 48 to 62 Hz at 0.008 G2 /Hz 65 to 300 Hz at 0.004 G2 /Hz 301 to 500 Hz at 0.0006 G 2 /Hz no errors PSD : 10 Hz at .05 G 2 /Hz 20 Hz at .055 G 2 /Hz, 300 Hz at .05 G 2 /Hz 301 Hz at .0014 G 2 /Hz 500 Hz at .
PRODUCT SPECIFICATIONS EMC/EMI Radiated Electromagnetic Field Emissions - EMC Compliance The hard disk drive mechanism is designed as a subassembly for installation into a suitable enclosure and is therefore not subject to Subpart J of Part 15 of FCC Rules (47CFR15) or the Canadian Department of Communications Radio Interference Regulations.
INSTALLATION SECTION 4 Handling and Installation Hard Drive Handling Precautions ◆ If the handling precautions are not followed, damage to the hard drive may result - which may void the warranty. ◆ During handling, NEVER drop, jar, or bump a drive. Handle the drive by its sides and avoid touching the printed circuit board assembly (PCBA). ◆ Hard drives are sensitive to electrostatic discharge (ESD) damage.
INSTALLATION Unpacking and Inspection Retain any packing material for reuse. Inspect the shipping container for evidence of damage in transit. Notify the carrier immediately in case of damage to the shipping container. As they are removed, inspect drives for evidence of shipping damage or loose hardware. If a drive is damaged (and no container damage is evident), notify Maxtor immediately for drive disposition.
INSTALLATION Figure 4 - 2 Single Pack Shipping Container (Option A) Figure 4 - 3 Single Pack Shipping Container (Option B) Repacking If a Maxtor drive requires return, repack it using Maxtor packing materials, including the antistatic bag. Physical Installation Recommended Mounting Configuration The Maxtor hard drive design allows greater shock tolerance than that afforded by larger, heavier drives.
INSTALLATION Before You Begin Important – Please Read Please read this installation section completely before installing the Maxtor hard drive. It gives general information for installing a Maxtor hard drive in a typical computer system. If you don’t understand the installation steps, have a qualified computer technician install the hard drive. Back up. Protect your Existing Data Periodic backup of important data is always a good idea.
INSTALLATION Install the Hard Drive in a Device Bay Refer to your computer user’s manual for specific mounting information. Be sure to secure the drive to the device bay with all four screws. Attach the Interface and Power Cables Do not force or rock the connectors into their sockets on the hard drive. Push them in straight until they are seated. Note: Maxtor Hard Drive Kits that carry an “H” in the kit number are Ultra ATA/100 compatible hard drives.
AT INTERFACE DESCRIPTION SECTION 5 AT Interface Description Interface Connector All Maxtor hard drives have a 40-pin ATA interface connector mounted on the PCBA. The drive may connect directly to the host; or it can also accommodate a cable connection (maximum cable length: 18 inches).
AT INTERFACE DESCRIPTION Pin Description Table PIN NAME PIN I/O RESET - 01 I D D0 17 I/O SIGNAL NAME SIGNAL DESC RIPTION Hos t Reset Reset si gnal from the host s ystem. Acti ve during power up and inacti ve after. Host Data Bus 16 bit bi-directional data bus between host and dri ve. Lower 8 bi ts used for register and EC C byte transfers. All 16 bi ts us ed for data transfers.
AT INTERFACE DESCRIPTION PIO Timing T IM IN G PARAMET ERS MODE 0 MODE 1 MODE 2 MODE 3 MODE 4 120 ns t0 Cycle Time (min) 600 ns 383 ns 240 ns 180 ns t1 Address vali d to DIOR-/D IOW - setup (min) 70 ns 50 ns 30 ns 30 ns 25 ns t2 D IOR-/DIOW- 16-bi t (min) 165 ns 125 ns 100 ns 80 ns 70 ns t2i D IOR-/DIOW- recovery ti me (min) 70 ns 25 ns t3 DIOW- data setup (min) 60 ns 45 ns 30 ns 30 ns 20 ns t4 DIOW- data hold (min) 30 ns 20 ns 15 ns 10 ns 10 ns t5 D IOR- data se
AT INTERFACE DESCRIPTION DMA Timing T IMIN G PARAMET ERS MODE 0 MODE 1 MODE 2 480 ns 150 ns 120 ns 215 ns 80 ns 70 ns 150 ns 60 ns t0 Cycle Ti me (min) tC DMAC K to DMARQ delay tD DIOR-/D IOW- (min) tE DIOR- data access (min) tF DIOR- data hold (min) 5 ns 5 ns 5 ns tG DIOR-/DIOW- data setup (min) 100 ns 30 ns 20 ns tH DIOW- data hold (min) 20 ns 15 ns 10 ns tI DM AC K to DIOR-/D IOW - setup (min) 0 0 0 tJ DIOR-/DIOW- to DMAC K hold (min) 20 ns 5 ns 5 ns tKr DIO
AT INTERFACE DESCRIPTION Ultra DMA Timing T IM IN G PARAMET ERS (all tim es in nanoseco nds ) MODE 0 MIN MAX MODE 1 MIN MAX MODE 2 MIN MAX MODE 3 MIN MAX MODE 4 MIN MAX MODE 5 MIN MAX tCYC Cycle Time (from STROB E edge to STROBE ed ge) 112 73 54 39 25 16.
AT INTERFACE DESCRIPTION t2CYC tCYC tCYC t2CYC DSTROBE at device tDVH tDVS tDVH tDVS tDVH DD(15:0) at device DSTROBE at host tDH tDS tDH tDS DD(15:0) at host Figure 5 - 5 Sustained Ultra DMA Data In Burst DMARQ (device) DMACK(host) tRP STOP (host) tSR HDMARDY(host) tRFS DSTROBE (device) DD(15:0) (device) Figure 5 - 6 Host Pausing an Ultra DMA Data In Burst 5–6 tDH
AT INTERFACE DESCRIPTION DMARQ (device) tMLI DMACK(host) tACK tLI tLI STOP (host) tACK tLI HDMARDY(host) tSS tIORDYZ DSTROBE (device) tZAH tAZ tDVS DD(15:0) tDVH CRC tACK DA0, DA1, DA2, CS0-, CS1- Figure 5 - 7 Device Terminating an Ultra DMA Data In Burst DMARQ (device) tLI tMLI DMACK(host) tZAH tAZ tRP tACK STOP (host) tACK HDMARDY(host) tRFS tLI tMLI tIORDYZ DSTROBE (device) tDVS DD(15:0) tDVH CRC tACK DA0, DA1, DA2, CS0-, CS1- Figure 5 - 8 Host Terminating an Ultra DMA Data In
AT INTERFACE DESCRIPTION DMARQ (device) tUI DMACK(host) tACK tENV STOP (host) tZIORDY tLI tUI DDMARDY(device) tACK HSTROBE (host) tDVS tDVH DD(15:0) (host) tACK DA0, DA1, DA2, CS0-, CS1- Figure 5 - 9 Initiating an Ultra DMA Data Out Burst t2CYC tCYC tCYC t2CYC HSTROBE at host tDVH tDVS tDVH tDVS tDVH DD(15:0) at host HSTROBE at device tDH tDS tDH tDS DD(15:0) at device Figure 5 - 10 Sustained Ultra DMA Data Out Burst 5–8 tDH
AT INTERFACE DESCRIPTION tRP DMARQ (device) DMACK(host) STOP (host) tSR DDMARDY(device) tRFS HSTROBE (host) DD(15:0) (host) Figure 5 - 11 Device Pausing an Ultra DMA Data Out Burst tLI DMARQ (device) tMLI DMACK(host) tLI tSS tACK STOP (host) tLI tIORDYZ DDMARDY(device) tACK HSTROBE (host) tDVS DD(15:0) (host) tDVH CRC tACK DA0, DA1, DA2, CS0-, CS1- Figure 5 - 12 Host Terminating an Ultra DMA Data Out Burst 5–9
AT INTERFACE DESCRIPTION DMARQ (device) DMACK(host) tLI tMLI tACK STOP (host) tRP tIORDYZ DDMARDY(device) tRFS tLI tMLI tACK HSTROBE (host) tDVS DD(15:0) (host) tDVH CRC tACK DA0, DA1, DA2, CS0-, CS1- Figure 5 - 13 Device Terminating an Ultra DMA Data Out Burst 5 – 10
HOST SOFTWARE INTERFACE SECTION 6 Host Software Interface The host communicates with the drive through a set of controller registers accessed via the host’s I/O ports. These registers divide into two groups: the Task File, used for passing commands and command parameters and the Control/Diagnostic registers. Task File Registers The Task File consists of eight registers used to control fixed disk operations.
HOST SOFTWARE INTERFACE Sector Count Register Holds the number of sectors to be sent during a Read or Write command, and the number of sectors per track during a Format command. A value of zero in this register implies a transfer of 256 sectors. A multisector operation decrements the Sector Count register. If an error occurs during such an operation, this register contains the remaining number of sectors to be transferred. Sector Number Register Holds the starting sector number for any disk operation.
HOST SOFTWARE INTERFACE Command Register Contains code for the command to be performed. Additional command information should be written to the task file before the Command register is loaded. When this register is written, the BUSY bit in the Status register sets, and interrupt request to the host clears; invalid commands abort. (Detailed information on interface commands is given in Section 7.
HOST SOFTWARE INTERFACE Summary CO MMAND N AME 6–4 CO M M AN D C OD E PA R A M E T E R S U S E D b7 b6 b5 b4 b3 b2 b1 b0 F SC SN C SD H R e c a li br a te 0 0 0 1 x x x x N N N N D R ea d S e c t o r(s ) 0 0 1 0 0 0 L x N Y Y Y Y R e ad D M A 1 1 0 0 1 0 0 x N Y Y Y Y W r ite S e c t o r(s ) 0 0 1 1 0 0 L x N Y Y Y Y W r i te D M A 1 1 0 0 1 0 1 x N Y Y Y Y W r ite V er i fy S e c t o r(s ) 0 0 1 1 1 1 0 0 N Y
HOST SOFTWARE INTERFACE Control Diagnostic Registers These I/O port addresses reference three Control/Diagnostic registers: I/O POR T R EAD WR ITE 3F6h Alternate Status F ixed Di sk C ontrol 3F7h D igital Input Not us ed Alternate Status Register Contains the same information as the Status register in the Task File. However, this register may be read at any time without clearing a pending interrupt.
HOST SOFTWARE INTERFACE Reset and Interrupt Handling Reset Handling One of three different conditions may cause a reset: power on, hardware reset or software reset. All three cause the interface processor to initialize itself and the Task File registers of the interface. A reset also causes a set of the Busy bit in the Status register. The Busy bit does not clear until the reset clears and the drive completes initialization. Completion of a reset operation does not generate a host interrupt.
INTERFACE COMMANDS SECTION 7 Interface Commands The following section describes the commands (and any parameters necessary to execute them), as well as Status and Error register bits affected.
INTERFACE COMMANDS Read Commands Read Sector(s) Reads from 1 to 256 sectors, as specified in the Command Block, beginning at the specified sector. (A sector count of 0 requests 256 sectors.) Immediately after the Command register is written, the drive sets the BSY bit and begins execution of the command. If the drive is not already on the desired track, an implied seek is performed. Once at the desired track, the drive searches for the data address mark of the requested sector.
INTERFACE COMMANDS Read DMA Multi-word DMA Identical to the Read Sector(s) command, except that 1. The host initializes a slave-DMA channel prior to issuing the command, 2. Data transfers are qualified by DMARQ and are performed by the slave-DMA channel and 3. The drive issues only one interrupt per command to indicate that data transfer has terminated and status is available.
INTERFACE COMMANDS Set Multiple Mode Enables the controller to perform Read and Write Multiple operations, and establishes the block count for these commands. Before issuing this command, the Sector Count register should be loaded with the number of sectors per block. The drives support block sizes of 2, 4, 8 and 16 sectors. When this command is received, the controller sets BSY and examines the Sector Count register contents.
INTERFACE COMMANDS Write Multiple Performs similarly to the Write Sector(s) command, except that: 1. The controller sets BSY immediately upon receipt of the command, 2. Data transfers are multiple sector blocks and 3. The Long bit and Retry bit is not valid. Command execution differs from Write Sector(s) because: 1. Several sectors transfer to the host as a block without intervening interrupts. 2. DRQ qualification of the transfer is required at the start of the block, not on each sector.
INTERFACE COMMANDS Mode Set/Check Commands Set Features Mode Enables or disables features supported by the drive. When the drive receives this command it: 1. 2. 3. 4. Sets BSY, Checks the contents of the Features register, Clears BSY and Generates an interrupt. If the value of the register is not a feature supported by the drive, the command is aborted.
INTERFACE COMMANDS Read Native Max Address This command returns the native maximum address. The native maximum address is the highest address accepted by the drive in the factory default condition. The native maximum address is the maximum address that is valid when using the SET MAX ADDRESS command. Set Max Individual SET MAX commands are identified by the value placed in the Features register.
INTERFACE COMMANDS Power Mode Commands Standby Immediate – 94h/E0h Spin down and do not change time out value. This command will spin the drive down and cause the drive to enter the STANDBY MODE immediately. If the drive is already spun down, the spin down sequence is not executed. Idle Immediate – 95h/E1h Spin up and do not change time out value. This command will spin up the spin motor if the drive is spun down, and cause the drive to enter the IDLE MODE immediately.
INTERFACE COMMANDS Default Power-on Condition The drive’s default power on condition is the ACTIVE MODE. Upon receiving a Power Mode command, except the SLEEP MODE command, the drive sets BSY and performs the requested power operation. Once the requested Power Mode change has begun, the drive resets BSY and generates an interrupt - without waiting for the drive to spin up or spin down.
INTERFACE COMMANDS Initialization Commands Identify Drive Allows the host to receive parameter information from the drive. When the command is received, the drive: 1. 2. 3. 4. Sets BSY, Stores the required parameter information in the sector buffer, Sets the DRQ bit and Generates an interrupt. The host may then read the information out of the sector buffer. Parameter words in the buffer follow. Note that all reserved bits or words should be zeroes.
INTERFACE COMMANDS -W OR D CONT ENT DESC RIPTION 50 51 - 52 53 64 65 66 67 68 69-74 75 Reserved Obsolete 15 -3 = reserved 2, 1 = the fi elds supported i n words 88 are vali d, 0 = the fields supported in words 88 are not vali d 1, 1 = the fi elds reports in words 64-70 are vali d, 0 = the fields reports i n words 64-70 are not vali d 0, 1 = the fi elds reports in words 54-58 are vali d, 0 = the fields reports i n words 54-58 are not vali d Number of current logi cal cyli nders Number of current logi ca
INTERFACE COMMANDS W OR D 83 84 85 86 88 127 128 129-130 131 132-159 160-255 7 – 12 CONT ENT DESC RIPTION Command sets s upported. If words 82 and 83 = 0000h or F FF Fh command set notification not supported. 15-10, as c urrently defined 9, 1 = Automati c Acoustic Management feature set supported 8-0, as c urrently defined Command set extensions supported. If words 84, 85 and 86 = 0000h or FFF Fh com mand set noti ficati on not supported.
INTERFACE COMMANDS Initialize Drive Parameters Enables the drive to operate as any logical drive type. The drive will always be in the translate mode because of Zone Density Recording, which varies the number of sectors per track depending on the zone. Through setting the Sector Count Register and Drive Head Register, this command lets the host alter the drive's logical configuration. As a result, the drive can operate as any equal to or less than capacity drive type.
INTERFACE COMMANDS Seek, Format and Diagnostic Commands Seek Initiates a seek to the track, and selects the head specified in the Command block. 1. 2. 3. 4. Sets BSY in the Status register, Initiates the Seek, Resets BSY and Generates an interrupt. The drive does not wait for the seek to complete before returning the interrupt. If a new command is issued to a drive during the execution of a Seek command, the drive will wait (with BSY active) for the Seek to complete before executing the new command.
INTERFACE COMMANDS S.M.A.R.T. Command Set Execute S.M.A.R.T. The Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.) command has been implemented to improve the data integrity and data availability of hard disk drives. In some cases, a S.M.A.R.T. capable device will predict an impending failure with sufficient time to allow users to backup their data and replace the drive before data loss or loss of service. In addition to S.M.A.R.T., DiamondMax drives support DST and all of its options. The S.
SERVICE AND SUPPORT SECTION 8 Service and Support Service Policy If a customer discovers a defect in a Maxtor hard drive, Maxtor will, at its option, repair or replace the disk drive at no charge to the customer, provided it is returned during the warranty period. Drives must be properly packaged in Maxtor packaging or Maxtor-approved packaging to obtain warranty service. Any unauthorized repairs or adjustments to the drive void the warranty.
SERVICE AND SUPPORT Asia/Pacific (APAC) Australia Vox Fax MaxFax BBS Languages supported: English + 61 2 9369 3662 + 61 2 9369 2082 + 61 2 9369 4733 + 61 2 9369 4293 Singapore Languages supported: English Contact local Maxtor sales office From Australia Hong Kong Indonesia Japan South Korea Malaysia New Zealand Singapore Toll Free Singapore Vox Singapore Fax Taiwan Thailand Dial 1-800-124-328 800-96-3387 803-65-6500 0031-65-3616 0078-65-800-6500 1-800-80-1126 0800-44-6542 1-800-481-6788 65-8520220 65-2
GLOSSARY GLOSSARY Glossary A access To obtain data from, or place data into, RAM, a register, or data storage device. access time The interval between the issuing of an access command and the instant that the target data may be read or written. Access time includes seek time, latency and controller overhead time. address A number, generally binary, distinguishing a specific member of an ordered set of locations.
GLOSSARY central processing unit (CPU) The heart of the computer system that executes programmed instructions. It includes the arithmetic logic unit (ALU) for performing all math and logic operations, a control section for interpreting and executing instructions, internal memory for temporary storage of program variables and other functions. channel A collection of electronic circuits used in the process of writing and reading information to and from magnetic media.
GLOSSARY digital magnetic recording See magnetic recording. direct access Access directly to memory location. (See random access). direct memory access (DMA) A mean of data transfer between the device and host memory without processor intervention. directory A listing of files maintained by the disk operation system (DOS) or a data base management system to enable a user to quickly access data files.
GLOSSARY frequency response A measure of how effectively a circuit or device transmits the different frequencies applied to it. In disk and tape drives this refers to the read/write channel. In disk drives, it can also refer to the dynamic mechanical characteristics of a positioning system. G gigabyte (GB) One billion bytes (one thousand megabytes) or 10E9. H hard error An error that is not able to be overcome by repeated readings and repositioning means.
GLOSSARY late window A data window that has been shifted in a late direction to facilitate data recovery. missing pulse A term used in surface certification. It is when a prerecorded signal is reduced in amplitude by a certain specified percentage. latency A delay encountered in a computer when waiting for a specific response. In a disk drive there is both seek latency and rotational latency.
GLOSSARY P parallelism 1. The condition of two planes or lines being parallel. Important in disk drives because a lack of it in mechanical assemblies can result in positioning inaccuracy. More precisely: planes-coplanar; lines-colinear. 2. Is the local variation in disk thickness measured independently of thickness itself. 3.
GLOSSARY S sector A logical segment of information on a particular track. The smallest addressable unit of storage on a disk. Tracks are made of sectors. sector pulse signal A digital signal pulse present in hard sectored drives which indicates the beginning of a sector. Embedded servo pattern or other prerecorded information may be present on the disk when sector is active. seek A random access operation by the disk drive.
GLOSSARY strobe offset signal A group of digital input signal levels which cause the read PLL and/or data decoder to shift the decoding windows by fractional amounts. Often early/late are modified when two signals are used. T thin-film head A magnetic transducer manufactured by deposition of magnetic and electrical materials on a base material contrasted with prior art mechanical methods.
