Maxtor VL20 manual

DiamondMax ® VL 20 92041U4, 91531U3 and 91021U2 All material contained herein Copyright © 1999 Maxtor Corporation. MaxFax™ is a trademark of Maxtor Corporation. DiamondMax ® , Maxtor ® and No Quibble ® Service are registered trademarks of Maxtor Corporation. Other brands or products are trademarks or registered trademarks of their respective[...]

Before Y ou Begin Thank you for your interest in the Maxtor DiamondMax ® VL 20 AT hard disk drives. This manual provides technical information for OEM engineers and systems integrators regarding the installation and use of DiamondMax hard drives. Drive repair should be performed only at an authorized repair center. For repair information, contact [...]

DIAMONDMAX VL 20 PRODUCT MANUAL i Contents Section 1 — Introduction Maxtor Corporation 1 - 1 Products 1 - 1 Support 1 - 1 Manual Organization 1 - 1 Abbreviations 1 - 1 Conventions 1 - 2 Key Words 1 - 2 Numbering 1 - 2 Signal Conventions 1 - 2 Section 2 — Product Description The DiamondMax ® VL 20 Product Features 2 - 2 Functional/Interface 2 -[...]

DIAMONDMAX VL 20 PRODUCT MANUAL ii Section 3 — Product Specifications Models and Capacities 3 - 1 Drive Configuration 3 - 1 Performance Specifications 3 - 1 Physical Dimensions 3 - 2 Power Requirements 3 - 3 Power Mode Definitions 3 - 3 Spin-up 3 - 3 Seek 3 - 3 Read/Write 3 - 3 Idle 3 - 3 Standby 3 - 3 Sleep 3 - 3 EPA Energy Star Compliance 3 - 3[...]

DIAMONDMAX VL 20 PRODUCT MANUAL iii Ultra Direct Memory Access (UDMA) 4 - 5 OS Requirements for Large Capacity Hard Drives 4 - 5 Hard Drive Identification 4 - 6 Identifying IDE Devices on the Interface 4 - 6 Jumper Settings 4 - 6 Systems Using Cable Select 4 - 6 Relationship to Other IDE Devices 4 - 6 Mounting Drive in System 4 - 7 Attaching Interf[...]

DIAMONDMAX VL 20 PRODUCT MANUAL iv Device Control Register 6 - 5 Digital Input Register 6 - 5 Reset and Interrupt Handling 6 - 6 Section 7 — Interface Commands Command Summary 7 - 1 Read Commands 7 - 2 Read Sector(s) 7 - 2 Read Verify Sector(s) 7 - 2 Read Sector Buffer 7 - 2 Read DMA 7 - 3 Read Multiple 7 - 3 Set Multiple 7 - 3 Write Commands 7 -[...]

DIAMONDMAX VL 20 PRODUCT MANUAL v Figures Figure Title Page 2 - 1 PCBA Jumper Location and Configuration 2 - 6 3 - 1 Outline and Mounting Dimensions 3 - 2 4 - 1 Multi-pack Shipping Container 4 - 2 4 - 2 Single-pack Shipping Container (Option A) 4 - 3 4 - 3 Single-pack Shipping Container (Option B) 4 - 3 4 - 4 Master, Slave and Cable Select Settings[...]

DIAMONDMAX VL 20 – INTRODUCTION 1 – 1 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, dow[...]

DIAMONDMAX VL 20 – INTRODUCTION 1 – 2 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 ?[...]

PRODUCT DESCRIPTION 2 – 1 SECTION 2 Product Description Maxtor DiamondMax ® VL 20 AT disk drives are 1-inch high, 3.5-inch diameter random access storage devices which incorporate an on-board ATA-5/Ultra DMA 66 controller. High capacity is achieved by a balanced combination of high areal recording density and the latest data encoding and servo t[...]

PRODUCT DESCRIPTION 2 – 2 Product Features Functional / Interface Maxtor DiamondMax VL 20 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[...]

PRODUCT DESCRIPTION 2 – 3 Logical Block Addressing The Logical Block Address (LBA) mode can only be utilized in systems that support this form of translation. The cylinder, head and sector geometry of the drive, as presented to the host, differs from the actual physical geometry. The host AT computer may access a drive of set parameters: number o[...]

PRODUCT DESCRIPTION 2 – 4 Cache Management Buffer Segmentation The data buffer is organized into two segments: the data buffer and the micro controller scratch pad. The data buffer is dynamically allocated for read and write data depending on the commands received. A variable number of read and write buffers may exist at the same time. Read-Ahead[...]

PRODUCT DESCRIPTION 2 – 5 Major HDA Components Drive Mechanism A brush-less DC direct drive motor rotates the spindle at 5,400 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 mot[...]

PRODUCT DESCRIPTION 2 – 6 Figure 2-1 PCBA Jumper Location and Configuration Cylinder Limitation Jumper Description On some older BIOS', primarily those that auto-configure the disk drive, a hang may occur. The Cylinder Limitation jumper reduces the capacity in the Identify Drive allowing large capacity drives to work with older BIOS'. T[...]

PRODUCT SPECIFICATIONS 3 – 1 SECTION 3 Product Specifications Models and Capacities Performance Specifications L E D O M4 U 1 4 0 2 93 U 1 3 5 1 92 U 1 2 0 1 9 e c a f r e t n I / r e l l o r t n o C d e t a r g e t n IA M D a r t l U / 5 - A T A d o h t e M g n i d o c n EE 2 7 1 / 6 1 L L R 4 R P e v a e l r e t n I1 : 1 m e t s y S o v r e Sd [...]

PRODUCT SPECIFICATIONS 3 – 2 Physical Dimensions 1 .028 max [25.9 mm] .25 ± .0 1 1 .122 ± .02 [28.4 mm] 1 .638 ± .005 [41 .61 mm] 1 .625 ± .02 4.000 ± .0 1 [1 0 1 .6 mm] 1 .75 ± .02 5.787 max [1 46.6 mm] 6 x 6-32 UNC T ap 4 x 6-32 UNC T ap 4.00 ± .0 1 [1 02.1 mm] 3.75 ± .0 1 [95.25 mm] Figure 3 - 1 Outline and Mounting Dimensions R E T E [...]

PRODUCT SPECIFICATIONS 3 – 3 Power Requirements 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. Idle The drive is spinning, the actuator is parked and powe[...]

PRODUCT SPECIFICATIONS 3 – 4 Reliability Specifications Annual Return Rate < 1.0% Annual Return Rate (ARR) indicates the average against products shipped. ARR includes all reasons for returns (failures, handling damage, NDF), but does not include inventory credit returns. Quality Acceptance Rate < 500 DPPM The quality acceptance rate indica[...]

PRODUCT SPECIFICATIONS 3 – 5 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 4 – 1 SECTION 4 Handling and Installation Pre-formatted Drive This Maxtor hard drive has been formatted at the factory. Do not use a low-level formatting program. 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, NE[...]

INSTALLATION 4 – 2 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 contai[...]

INSTALLATION 4 – 3 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 DiamondMax ® drive design allows greater[...]

INSTALLATION 4 – 4 1 Before Y ou Begin IMPORTANT – PLEASE READ! Please read this Installation Sheet 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 h[...]

INSTALLATION 4 – 5 3 Hard Drive Identification IDE stands for Integrated Drive Electronics and EIDE is Enhanced IDE. The IDE or EIDE interface is designed to support two devices – typically hard drives – on a single ribbon cable through one 40 pin connector on the mother board or interface card. Some mother boards and interface cards may have[...]

INSTALLATION 4 – 6 4 Mounting Drive in System Turn the computer OFF, disconnect the power cord and remove the cover. Refer to the computer user’s manual for information on removing the cover. Each system manufacturer uses different types of cases, including desktop, mini-tower, full tower and other special configurations. As a result, there are[...]

INSTALLATION 4 – 7 5 At tac hing Interface and P o w er Cables In order for the computer to recognize that the Maxtor hard drive is in the system, the power cable and IDE interface cable must be properly connected. 1 Attach an available IDE interface connector to J1 on the Maxtor hard drive. The striped or colored edge of the IDE interface cable [...]

INSTALLATION 4 – 8 7 System Setup The following procedures are designed for systems using the DOS 5.0 (or higher), Windows 95 and Windows 98 operating systems. For other operating systems (e.g., Windows NT, OS2, UNIX, LINUX and Novell NetWare), refer to the operating system user’s manual for the BIOS setting and other installation requirements.[...]

INSTALLATION 4 – 9 drive parameters must be set using the User Definable Type (UDT). Set the Cylinder, Head and Sector values with the values listed on the drive label. The drive label is located on the top cover of the drive. The fields LZone (Landing Zone) and WPcom (Write Pre-comp) are not used by the Maxtor hard drive. These fields may be set[...]

INSTALLATION 4 – 10 3 If the BIOS was set to AUTO DETECT, follow the instructions in Section 7 to prepare the hard drive using the MaxBlast installation software. If other BIOS settings were used, access the system BIOS SETUP program and set the parameters to a User Definable Type with 4,092 cylinders, 16 heads and 63 sectors per track for the Ma[...]

AT INTERFACE DESCRIPTION 5 – 1 SECTION 5 A T Interface Description Interface Connector All DiamondMax ® VL 20 AT 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 (max cable length: 18 inches). System Connector (blue) Drive 0 - Master (black[...]

AT INTERFACE DESCRIPTION 5 – 2 Pin Description Table E M A N N I PN I PO / IE M A N L A N G I SN O I T P I R C S E D L A N G I S - T E S E R1 0I t e s e R t s o H . r e t f a e v i t c a n i d n a p u r e w o p g n i r u d e v i t c A . m e t s y s t s o h e h t m o r f l a n g i s t e s e R 0 D D7 1O / Is u B a t a D t s o H r e t s i g e r r o [...]

AT INTERFACE DESCRIPTION 5 – 3 S R E T E M A R A P G N I M I T0 E D O M1 E D O M2 E D O M3 E D O M4 E D O M 0 t) n i m ( e m i T e l c y Cs n 0 0 6s n 3 8 3s n 0 4 2s n 0 8 1s n 0 2 1 1 t) n i m ( p u t e s - W O I D / - R O I D o t d i l a v s s e r d d As n 0 7s n 0 5s n 0 3s n 0 3s n 5 2 2 t) n i m ( t i b - 6 1 - W O I D / - R O I Ds n 5 6 1s[...]

AT INTERFACE DESCRIPTION 5 – 4 DMA Timing S R E T E M A R A P G N I M I T0 E D O M1 E D O M2 E D O M 0 t) n i m ( e m i T e l c y Cs n 0 8 4s n 0 5 1s n 0 2 1 C ty a l e d Q R A M D o t K C A M D D t) n i m ( - W O I D / - R O I Ds n 5 1 2s n 0 8s n 0 7 E t) n i m ( s s e c c a a t a d - R O I Ds n 0 5 1s n 0 6 F t) n i m ( d l o h a t a d - R O [...]

AT INTERFACE DESCRIPTION 5 – 5 Ultra DMA Timing S R E T E M A R A P G N I M I T ) s d n o c e s o n a n n i s e m i t l l a ( 0 E D O M1 E D O M2 E D O M3 E D O M4 E D O M N I MX A MN I MX A MN I MX A MN I MX A MN I MX A M t C Y C e m i T e l c y C) e g d e E B O R T S o t e g d e E B O R T S m o r f (2 1 13 74 59 35 2 2 t C Y C e m i t e l c y c[...]

AT INTERFACE DESCRIPTION 5 – 6 Figure 5 - 5 Sustained Ultra DMA Data In Burst t DVH DSTROBE at d evice DD(15:0) at d evice DSTROBE at ho s t DD(15:0) at ho s t t DVH t CYC t CYC t DVS t DVS t DH t DS t DH t DS t 2CYC t DH t DVH t 2CYC DMARQ (device) DMACK- (host) STOP (host) HDMARDY- (host) DSTROBE (device) DD(15:0) (device) t SR t RFS t RP Figur[...]

AT INTERFACE DESCRIPTION 5 – 7 t AZ t IORDYZ CRC DMARQ ( device ) DMACK- (host) STOP (host) HDMARDY- (host) DSTROBE ( device ) DD(15:0) DA0, DA1, DA2, CS0-, CS1- t ACK t LI t MLI t DVS t LI t ACK t ACK t ZAH t DVH t SS t LI Figure 5 - 7 Device Terminating an Ultra DMA Data In Burst t DVH CRC t AZ DMARQ (device) DMACK- (host) STOP ( host ) HDMARDY[...]

AT INTERFACE DESCRIPTION 5 – 8 t DH t DS t DVH HSTROBE at ho s t DD(15:0) at ho s t HSTROBE at d evice DD(15:0) at d evice t DVH t CYC t CYC t DVS t DVS t DS t DH t 2CYC t DH t DVH t 2CYC DMARQ (device) DMACK- ( host ) STOP (host) DDMARDY- (device) HSTROBE (host) DD(15:0) (host) DA0, DA1, DA2, CS0-, CS1- t UI t ACK t ENV t ZIORDY t LI t DVS t DVH[...]

AT INTERFACE DESCRIPTION 5 – 9 DMARQ (device) DMACK- (host) STOP (host) DDMARDY- (device) HSTROBE (host) DD(15:0) (host) t SR t RFS t RP Figure 5 - 11 Device Pausing an Ultra DMA Data Out Burst DMARQ (device) DMACK- (host) STOP (host) DDMARDY- (device) HSTROBE (host) DD(15:0) (host) DA0, DA1, DA2, CS0-, CS1- t ACK t LI t MLI t DVS t LI t LI t ACK[...]

AT INTERFACE DESCRIPTION 5 – 10 DMARQ (device) DMACK- (host) STOP ( host ) DDMARDY- ( device ) HSTROBE (host) DD(15:0) (host) DA0, DA1, DA2, CS0- , CS1- t ACK t MLI t DVS t LI t LI t ACK CRC t DVH t ACK t IORDYZ t MLI t RP t RFS Figure 5 - 13 Device Terminating an Ultra DMA Data Out Burst[...]

HOST SOFTWARE INTERFACE 6 – 1 SECTION 6 Host So ftw are 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[...]

HOST SOFTWARE INTERFACE 6 – 2 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 multi- sector operation decrements the Sector Count register. If an error occurs during such a[...]

HOST SOFTWARE INTERFACE 6 – 3 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 [...]

HOST SOFTWARE INTERFACE 6 – 4 D E S U S R E T E M A R A P E D O C D N A M M O C E M A N D N A M M O C 7 b6 b5 b4 b3 b2 b1 b0 bF C SN SC H D S e t a r b i l a c e R 0 00 1 xxxx NNNN D ) s ( r o t c e S d a e R 0 0 1 000 Lx N YY Y Y A M D d a e R 1 1 0 0 1 0 0 x N YYY Y ) s ( r o t c e S e t i r W 0 0 1 1 0 0 L x N YYY Y A M D e t i r W 1 1 0 01 01[...]

HOST SOFTWARE INTERFACE 6 – 5 Control Diagnostic Registers These I/O port addresses reference three Control/Diagnostic registers: T R O P O / ID A E RE T I R W h 6 F 3s u t a t S e t a n r e t l Al o r t n o C k s i D d e x i F h 7 F 3t u p n I l a t i g i Dd e s u t o N Alternate Status Register Contains the same information as the Status regist[...]

HOST SOFTWARE INTERFACE 6 – 6 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 [...]

INTERFACE COMMANDS 7 – 1 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. Read Commands Read Sector(s) Read Verify Sector(s) Read Sector Buffer Read DMA Multi-word DMA Ultra DMA Read Multiple Set Multiple Write Commands Wri[...]

INTERFACE COMMANDS 7 – 2 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 d[...]

INTERFACE COMMANDS 7 – 3 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[...]

INTERFACE COMMANDS 7 – 4 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 comma[...]

INTERFACE COMMANDS 7 – 5 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 tran[...]

INTERFACE COMMANDS 7 – 6 Set Feature Commands Set Features Mode Enables or disables features supported by the drive. When the drive receives this command it: 1 . Sets BSY, 2 . Checks the contents of the Features register, 3 . Clears BSY and 4 . Generates an interrupt. If the value of the register is not a feature supported by the drive, the comma[...]

INTERFACE COMMANDS 7 – 7 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[...]

INTERFACE COMMANDS 7 – 8 When enabling the Automatic Power Down sequence, the value placed in the Sector Count register is multiplied by five seconds to obtain the Time-out Interval value. If no drive commands are received from the host within the Time-out Interval, the drive automatically enters the STANDBY mode. The minimum value is 5 seconds. [...]

INTERFACE COMMANDS 7 – 9 Initialization Commands Identify Drive Allows the host to receive parameter information from the drive. When the command is received, the drive: 1 . Sets BSY, 2 . Stores the required parameter information in the sector buffer, 3 . Sets the DRQ bit and 4 . Generates an interrupt. The host may then read the information out [...]

INTERFACE COMMANDS 7 – 10 D R O WN O I T P I R C S E D T N E T N O C 0 5d e v r e s e R 1 5e d o m r e f s n a r t a t a d O I P = 8 - 5 1 d e s u t o n = 0 - 7 2 5e d o m r e f s n a r t a t a d A M D = 8 - 5 1 d e s u t o n = 0 - 7 3 5d e v r e s e r = 5 1 d i l a v t o n e r a 8 8 s d r o w n i d e t r o p p u s s d l e i f e h t = 0 , d i l a[...]

INTERFACE COMMANDS 7 – 11 D R O WN O I T P I R C S E D T N E T N O C 3 8 t o n n o i t a c i f i t o n t e s d n a m m o c h F F F F r o h 0 0 0 0 = 4 8 d n a 3 8 , 2 8 s d r o w f I . d e t r o p p u s s t e s d n a m m o C . d e t r o p p u s o r e z o t d e r a e l c e b l l a h s = 5 1 e n o o t t e s e b l l a h s = 4 1 d e v r e s e r = 1 -[...]

INTERFACE COMMANDS 7 – 12 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[...]

INTERFACE COMMANDS 7 – 13 Seek, Format and Diagnostic Commands Seek Initiates a seek to the track, and selects the head specified in the Command block. 1 . Sets BSY in the Status register, 2 . Initiates the Seek, 3 . Resets BSY and 4 . Generates an interrupt. The drive does not wait for the seek to complete before returning the interrupt. If a ne[...]

INTERFACE COMMANDS 7 – 14 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 user[...]

SERVICE AND SUPPORT 8 – 1 SECTION 8 Service and Support Service and Support Service and Support Service and Support Service and Support Service Policy Service Policy Service Policy Service Policy 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[...]

SERVICE AND SUPPORT 8 – 2 Asia/Pacific (APAC) Australia Languages supported: English Vo x + 61 2 9369 3662 Fax + 61 2 9369 2082 MaxFax + 61 2 9369 4733 BB S + 61 2 9369 4293 Sin gap ore Languages supported: English Contact local Maxtor sales office From Di al Australia 1-800-124-328 Ho ng K ong 800-96-3387 I nd o n es i a 803-65-6500 J a p an 003[...]

GLOSSARY GL – 1 GLOSSAR Y Glossary Glossary Glossary Glossary Glossary A A A A 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 control[...]

GLOSSARY GL – 2 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 function[...]

GLOSSARY GL – 3 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 ma[...]

GLOSSARY GL – 4 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 G G G G gigabyte (GB) One billion bytes (one th[...]

GLOSSARY GL – 5 late window A data window that has been shifted in a late direction to facilitate data recovery. 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. The time required for the addressed sector to arrive under the head after the head is po[...]

GLOSSARY GL – 6 P P P P 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. The a[...]

GLOSSARY GL – 7 S S S S 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 b[...]

GLOSSARY GL – 8 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 T T T T thin-film head A magnetic transducer manufactured by deposition of magnetic and electrical materials on a b[...]