Seagate ST15230ND, ST15230N, HAWK 4 User Manual

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HAWK 4 Family:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ST15230N/ND

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Product Manual, Volume 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

HAWK 4 Family:

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

ST15230N/ND

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Product Manual, Volume 1

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Publication Number: 77767472 Re vision F March 1996

Seagate®, Seagate Technology® and the Seagate logo are registered trademarks of Seagate Technology, Inc. Ha wk™, SeaF AX, SeaF one, SeaTDD and SeaBO ARD are trademarks of Seagate Technology, Inc. Other product names are registered tr ademarks or trademarks of their owners.

Seagate reserves the right to change, without notice, product offerings or specifications. No par t of this publication may be reproduced in any f orm without written permission of Seagate Technology , Inc.

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F v _____________________________________________________________________________________

Revision status summary sheet

Revision Authority Date Writer/Eng. Sheets Affected

A Issue 09/01/94 D. Ashby v thru viii, 1 thru 60.

Brent Douglas

B PLD: 87088 11/02/94 D. Ashby v, 12, 13, 38 - 40

C PLD: 87187 06/05/95 Brent Douglas v, 23, 36 D PLD:87236 08/30/95 D. Ashby 1v and 34 E PLD: 87305 1/24/96 D . Ashby v, vi, 2, 12 and 21 F PLD: 87334 v and 18

Brent Douglas

Notice. Product Manual 77767472 is Volume 1 of a tw o Volume document with the SCSI interface information

in the V olume 2 SCSI Interface Pr oduct Man ual, P/N 77738479.

If the SCSI Interface information is needed the Volume 2 Interface Manual should be ordered, P/N

77738479.

vi Product Manual - Hawk 4 Family SCSI-2 (Volume 1), Rev. F _____________________________________________________________________________________

T able of contents

1.0 Scope.......................................................................................................................................... 1

2.0 Applicable standards and reference documentation.............................................................. 2

2.1 Standards ....................................................................................................................... 2

2.2 Electromagnetic Compliance for the European Union..................................................... 2

2.3 Applicable reference documents..................................................................................... 2

3.0 General description................................................................................................................... 3

4.0 Standards features .................................................................................................................... 5

4.1. Performance ................................................................................................................... 5

4.1.1 Reliability............................................................................................................ 5

4.2 Unformatted and formatted capacities ............................................................................ 6

4.3 Options (factory installed) ............................................................................................... 6

4.4 Optional accessories (user installed) .............................................................................. 6

4.5 Installation....................................................................................................................... 7

5.0 Performance characteristics..................................................................................................... 8

5.1 Internal drive characteristics (transparent to user) .......................................................... 8

5.2 SCSI drive Seek, Read and Write performance characteristics (Visible to User) ............ 8

5.2.1 Access time........................................................................................................ 8

5.2.2 Format drive command ex ecution time............................................................... 9

5.2.3 Read data command ex ecution time................................................................... 9

5.2.4 Write data command execution time................................................................... 9

5.3 Generalized performance characteristics........................................................................ 10

5.3.1 Notes for sections 5.2 and 5.3 ............................................................................ 11

5.4 Start/stop time ................................................................................................................ 12

5.5 Prefetch/multi segmented cache control ......................................................................... 12

5.5.1 Cache operation ................................................................................................. 12

5.5.2 Prefetch operation .............................................................................................. 13

5.6 Caching write data .......................................................................................................... 14

6.0 Reliability specifications ........................................................................................................... 15

6.1 Error rates....................................................................................................................... 15

6.1.1 Read errors........................................................................................................ 15

6.1.2 Environmental interf erence ................................................................................ 15

6.1.3 Write errors ........................................................................................................ 16

6.1.4 Seek errors ........................................................................................................ 16

6.2 Reliability and service ..................................................................................................... 16

6.2.1 Mean time between failure ................................................................................. 16

6.2.2 Prev entive maintenance..................................................................................... 16

6.2.3 Service life ......................................................................................................... 16

6.2.4 Service philosophy............................................................................................. 17

6.2.5 Installation.......................................................................................................... 17

6.2.6 Service tools ...................................................................................................... 17

6.2.7 Product Warranty ............................................................................................... 17

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F vii _____________________________________________________________________________________

T able of contents

7.0 Physical/electrical specifications ............................................................................................. 18

7.1 AC pow er requirements .................................................................................................. 18

7.2 DC power requirements .................................................................................................. 18

7.2.1 Conducted noise immunity................................................................................. 19

7.2.2 Po wer sequencing.............................................................................................. 19

7.2.3 12 V - current profile........................................................................................... 19

7.3 Heat/power dissipation.................................................................................................... 20

7.4 Environmental limits........................................................................................................ 20

7.4.1 T emper ature....................................................................................................... 21

7.4.2 Relative humidity................................................................................................ 23

7.4.3 Effective altitude (sea le v el ref)........................................................................... 23

7.4.4 Shock and vibration............................................................................................ 23

7.4.5 Air cleanliness.................................................................................................... 25

7.5 Electromagnetic compatibility.......................................................................................... 25

7.5.1 Electromagnetic susceptibility ............................................................................ 25

7.6 Mechanical specifications ............................................................................................... 26

7.6.1 Drive orientation................................................................................................. 27

7.6.2 Cooling............................................................................................................... 27

7.6.3 Drive mounting................................................................................................... 27

8.0 Media characteristics ................................................................................................................ 28

8.1 Media description............................................................................................................ 28

9.0 Defect and error management .................................................................................................. 29

9.1 Drive internal defects/errors............................................................................................ 29

9.2 SCSI systems error considerations................................................................................. 29

10.0 Option/configuration headers................................................................................................... 30

10.1 Drive ID/option select header.......................................................................................... 30

10.2 Grounding....................................................................................................................... 32

11.0 Interface requirement ................................................................................................................ 33

11.1 General description......................................................................................................... 33

11.2 SCSI interface messages supported............................................................................... 33

11.3 SCSI interface commands supported ............................................................................. 34

11.3.1 Inquiry data ........................................................................................................ 36

11.3.2 Mode sense data ............................................................................................... 37

11.4 SCSI bus conditions and miscellaneous features supported........................................... 40

11.5 Synchronous data transfer.............................................................................................. 41

11.5.1 Synchronous data transfer periods supported.................................................... 41

11.5.2 REQ/ACK offset ................................................................................................. 41

11.6 Physical interface............................................................................................................ 41

11.6.1 DC cable and connector..................................................................................... 43

11.6.2 Physical characteristics...................................................................................... 43

11.6.3 Connector requirements..................................................................................... 45

11.6.4 Electrical description .......................................................................................... 49

11.7 Disc drive timing ............................................................................................................. 54

viii Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F _____________________________________________________________________________________

T able of contents

12.0 Options....................................................................................................................................... 56

12.1 Front panel...................................................................................................................... 56

12.2 Single unit shipping pack ................................................................................................ 56

12.3 Installation Guide ............................................................................................................ 56

13.0 Accessories ............................................................................................................................... 57

13.1 Front panel kit ................................................................................................................. 57

13.2 Additional Installation Guide copies ................................................................................ 57

14.0 Te chnical support services....................................................................................................... 58

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F 1 ______________________________________________________________________________________

1.0 Scope

This specification describes the Seagate Technology, Inc. Hawk 4 Family Disc Driv e. This high capacity, high performance member of the Seagate 3.5 inch rigid disc family is a companion product to the ST12400 drive family . It has an embedded SCSI controller . Perf ormance information is given in Section 5. The Hawk 4 F amily interface is defined for functional compatibility to a subset of the Seagate SCSI Interf ace Specification 77738479, and the ANSI SCSI-2 and SCSI-3 standards. The Model Hawk 4 Family drives are classified as “Intelligent” peripherals. The Ha wk 4 Family provides Le vel 2 conf ormance (highest level) with the ANSI SCSI-1 standard. Details of the Hawk 4 F amily drive SCSI implementation are provided in Section 11 of this specification, (V ol.

1) and in the SCSI Interface Product Manual P/N 77738479 (Vol. 2; Ver. 2). The Hawk 4 family of drives consists of the ST15230N/ND drives . From this point on in this Product Manual the ref erence to Ha wk 4 F amily is ref erred to as “the drive” (unless

reference to individual models are necessary). The drive printed circuit board is referred to as a PCB.

Figure 1-1. Hawk 4 family drive

SEAGATE

2 Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F ______________________________________________________________________________________

2.0 Applicable standards and reference documentation

The drive has been developed as a system peripheral to the highest standards of design and construction. The drive depends upon its host equipment to provide adequate power and en vironment in order to achie ve optimum performance and compliance with applicable industry and governmental regulations. Special attention must be given in the areas of saf ety , power distribution, shielding, audib le noise control, and temperature regulation. In particular , the drive must be securely mounted in order to guarantee the specified performance characteristics.

2.1 Standards

The Hawk 4 Family complies with Seagate standards as noted in the appropriate sections of this specification and the Seagate SCSI Interface Specification, P/N 77738479 (Vol.2, Version 2).

The Hawk 4 F amily is a UL Recognized component per UL 1950 and a CSA Certified component per CAN/ CSA-C22.2 No. 950-M89. It also meets the requirements of DIN VDE 0805:1993 and EN60950: 1992 (IEC

950). The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to

use. As such the dr ive is supplied as a subassembly and is not subject to Subpart J of Part 15 of the FCC Rules and Regulations nor the Radio Interference Regulations of the Canadian Department of Communications. Howev er , the unit has been tested using proper shielding and grounding and found to be compliant with Class A limits of the FCC Rules and the Regulations of The Canadian Department of Communications.

The physical design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides reasonable shielding. As such, the drive is capable of meeting the Class B limits of the FCC Rules and Regulations of the Canadian Department of Communication. Howe ver , it is the users responsibility to assure that the drive meets the appropriate EMI requirements in their system. Shielded I/O cab les may be required if the enclosure does not provide adequate shielding. If the I/O cab les are external to the enclosure, shielded cables should be used, with the shields grounded to the enclosure and to the host controller .

Caution. To avoid potential service problems, observe the follo wing precautions:

The Manufacturers installed labels must not be removed from the drive or covered with additional labels, as they contain inf ormation required when servicing the product.

2.2 Electromagnetic Compliance for the European Union

If this model has the CE Marking it complies with the European Union requirements of the Electromagnetic Compatibility Directive 89/336/EEC of 03 May 1989 as amended by Directive 92/31/EEC of 28 April 1992 and Directive 93/68/EEC of 22 July 1993.

Seagate uses an independent laboratory to confirm compliance to the above directives. The drive was tested in a representative system for typical applications. The selected system represents the most popular characteristics for test platforms. The system configurations include:

• 486, Pentium, and Power PC Microprocessors • Keyboard

• 3.5-inch Floppy Disc Drive • Monitor/Display Although the test system with this Seagate model complies to the directives, we cannot guarantee that all

systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance and provide CE Marking for their product.

2.3 Applicable reference documents

Installation Guide Seagate P/N 77767474 Product Manual - SCSI Interface Seagate P/N 77738479 ANSI Small Computer System Interface (SCSI): Document Number ANSI3.131-1986 (X3T9/84.40 Re v. 1B) (X3T9.2/82-2 Rev. 17B), X3T9.2/86-109 Re vision 10H (SCSI-2) and X3T9.2-184 Re v. 4 (SCSI-3).

Seagate Package T est Requirements P/N 30190-001 (pac kages under 100 lbs) Seagate Package T est Requirements P/N 30191-001 (packages o v er 100 lbs)

In case of conflict between this document and any referenced document, this document shall take precedence.

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F 3 ______________________________________________________________________________________

3.0 General description

The drives are a member of a family of low cost, high performance, highly reliable, random access storage devices designed to meet the needs of the OEM marketplace.

The drive records and recovers data on 3.7 inch (95 mm) fix ed discs . The drive supports the Small Computer System Interface-2 (SCSI) as described in the ANSI SCSI-1, SCSI-

2 and SCSI-3 Interface Specifications to the extent described in this product manual (Vol. 1), which defines the product performance characteristics of the Hawk 4 Family of drives, and the SCSI Interface Product Manual P/N 77738479 (Vol. 2, Version 2) which describes the general interface characteristics of this and other families of Seagate 3.5-inch drives.

The drive interface supports multiple initiators, disconnect/reconnect, self configuring host software and automatic features that reliev e the host from the necessity of knowing the physical characteristics of the targets (logical block addressing is used).

The Head/Disc Assembly (HDA) is environmentally sealed at the factory. Air recirculates within the HDA through a nonreplaceable filter to maintain a contamination free head/disc environment.

Refer to Figure 3.0-1 for an e xploded view of the drive . NEVER disassemble the Head/Disc Assembly (HD A). This exploded view is f or information only . Do not attempt to service items in the sealed environmental enclosure (heads, media, actuator , etc.) as this requires special facilities . The driv e contains no parts replaceable by the user . The drive w arranty is voided if the HDA is opened.

The Hawk 4 Family driv es use a dedicated landing zone at the innermost radius of the media to eliminate the possibility of destroying or degrading data by landing in the data zone. The drive automatically goes to the landing zone when the power is remov ed.

The Hawk 4 Family drives incor porate an automatic shipping lock which prevents potential damage to the heads and discs that result from movement during shipping and handling. The shipping lock disengages when power is applied to the drive and the head load process begins.

The Hawk 4 F amily drives decode Tr ack 0 location from the dedicated servo surface to eliminate mechanical transducer adjustments and related reliability concerns.

The Hawk 4 F amily drives use a high performance actuator assembly that consists of a low inertia, balanced, patented, straight arm design that provides excellent performance with minimum pow er dissipation.

4 Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F ______________________________________________________________________________________

Figure 3.0-1. Hawk 4 family drive

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F 5 ______________________________________________________________________________________

4.0 Standard features

The Hawk 4 F amily has the f ollo wing standard f eatures:

• Integrated SCSI Controller

• Single Ended and Differential SCSI drivers and receivers

• Asynchronous and Synchronous data transfer protocol

• Firmware downloadable via SCSI interf ace

• Selectable sector size from 256 to 4096 bytes/sector

• Programmable sector reallocation scheme

• Flawed sector reallocation at format time

• Programmable auto write and read reallocation

• Reallocation of defects on command (Post Format)

• 96 bit Reed-Solomon error correcting code

• Sealed Head/Disc Assembly

• No preventative maintenance or adjustment required

• Dedicated head landing zone

• Automatic shipping lock

• Automatic Adaptive Thermal Compensation

• Patented Tri-Phase Servo with embedded Grey Code track address to guarantee servo positioning.

• Self diagnostics performed at power on

• 1:1 Interleave

• Zoned Bit Recording (ZBR)

• Vertical, horizontal, or top down mounting

• Dynamic spindle brake

• 512 K byte data buffer

• Permanently mounted terminators (for model ST15230N only), enabled by installation of a jumper plug.

4.1 Performance

• Programmable multi-segmentable cache buffer

• 5411 r/min Spindle. Av er age latency = 5.54 ms

• Command Queuing of up to 64 commands per initiator

• Background processing of queue

• Supports start and stop commands

• Low audible noise for office environment

• Low power consumption

4.1.1 Reliability

• 800,000 hour MTBF

• Adaptive seek velocity. Improved seek perf ormance

• LSI circuitry

• Balanced low mass rotary voice coil actuator

• 5 year warranty

6 Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F ______________________________________________________________________________________

4.2 Unformatted and formatted capacities

Formatted capacity depends on the number of spare reallocation sectors reserved and the number of bytes per sector. The follo wing tab le shows some

Spare sectors or cylinders N/ND reserved for reallocation MB

No spares 4319 4596 Twelve spare sector per cylinder [2] 2 spare cylinders per Unit [3] 4294 4546 One spare sector per cylinder 2 spare cylinders per Unit [3] 4315 4590 Unformatted capacity 5170

Notes.

[1] Bytes per sector. Sector size selectable at format time. Users having the necessary equipment may

modify the data block size before issuing a format command and obtain different formatted capacities than those listed. User available capacity depends on spare reallocation scheme selected. See Mode

Select Command and Format Command in the SCSI Interface Product Manual P/N 77738479. [2] All twelve spare sectors are on one track. [3] Spare cylinders are on the two inner tracks.

typical

formatted capacities.

512 [1] 1024 [1]

The standard OEM model is as follows:

Formatted Data Block Size* Unformatted 512 Byte/Sector

ST15230N/ND 4294 MB 5170 MB *Twelve spare sectors per cylinder (all twelve spare sectors are on one track), two spare cylinders/unit. Drives are shipped with an Installation Guide P/N 77767474 unless otherwise specified.

4.3 Options (factory installed)

The capacities shown in paragraph 4.2 are av ailable upon request. Other capacities can be ordered depending on sparing scheme and sector size requested.

The following options are incorporated at the time of production. See Section 12.0.

• Front panel (green LED) - See Figure 3.0-1

• Single Unit shipping pack

• Installation Guide P/N 77767474

4.4 Optional accessories (user installed)

The following accessories are av ailab le . All kits may be installed in the field. See Section 13.0.

• Front Panel Kit (with green LED) - See Figure 3.0-1

• Single Unit shipping pack kit

• Adapter Accessory Frame Kit P/N 75790701 (adapts 3.5-inch drive to fit in 5.25-inch drive mounting

space)

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F 7 ______________________________________________________________________________________

4.5 Installation

For option jumper locations and definitions refer to Figure 10.1-1. Drive default mode parameters are not normally needed for installation. Refer to Section 11.3.2 for default mode parameters if they are needed.

• Ensure that the SCSI ID of the drive is not the same as the host adapter . Most host adapters use SCSI ID

• If multiple devices are on the bus set the drive SCSI ID to one that is not presently used by other de vices on

the bus.

• If the drive is the only device on the bus, attach it to the end of the SCSI bus cable . Permanently installed

terminators must be enabled on the drive for ST15230N models using a jumper plug (see Figure 10.1-1), For the ST15230ND model, terminators must be installed external to the drive. These e xternal terminators must be provided by the user , systems integrator or host equipment manuf acturer . Ref er to section 11.6.4.3.

• If the drive is attached to a bus that contains other de vices , and the new drive is not attached to the end of

the bus, the terminator enable jumper should be removed from the ne w drive .

• Set all appropriate option jumpers for desired operation prior to power on. If jumpers are changed after

power has been applied, recycle the drive power to mak e the ne w settings effective.

• Installation instructions are provided by host system documentation or with any additionally purchased

drive installation software. If necessary see section 14.0 for Seagate support services telephone numbers.

• The manufacturers installed labels must not be removed from the drive or co vered with additional labels, as

they contain information required when servicing the product.

Formatting

• It is not necessary to low level f ormat this drive. The drive is shipped from the f actory low le vel formatted in

512 byte sectors.

• Reformat the drive if one of the following occurs.

- A different sector size is selected.

- A different spare sector allocation scheme is selected.

8 Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F ______________________________________________________________________________________

5.0 Performance characteristics

5.1 Internal drive characteristics (transparent to user)

Drive Capacity 5170 MByte (UNF) Read/Write Heads 19 Bytes/Track 68155 Bytes (UNF, Avg) Bytes/Surface 272 Mbytes (UNF) Tracks/Surface , T otal 3992 Tracks (user accessible) Tracks/Inch 4200 TPI Servo Heads 1 1 Internal Data Rate 33.9 to 61.0 Mbits/sec (v ariable with z one) Disc Rotational Speed 5411 +0.5% r/min Aver age Rotational Latency 5.54 ms

5.2 SCSI Seek, Read and Write performance characteristics (visible to user) [8]*

Refer to Section 11.7 and to the SCSI-2 Interface Product Man ual 77738479 for additional timing details .

5.2.1 Access time

Includes Controller Overhead with no Disconnects [1] [4]

Read Write

Average - Typical [3] 10.4 11.4

Max. [2] 11.9 13.4

Single T rack- T ypical [3] 2.1 2.5

Max. [2] 3.8 4.3

Full Stroke - Typical [3] 20.6 21.4

Max. [2] 23.9 24.9

*[ ] All notes are listed in section 5.3.1.

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F 9 ______________________________________________________________________________________

5.2.2 Format drive command execution time (minutes) [1]

Maximum (with verify) 70 Min. Maximum (no verify) 45 Min

5.2.3 Read data command execution time [4]

(512 byte sector size, without disconnect and with read look ahead cache disabled.) Latency time is included.

a. From CDB reception to the drive request f or the first data byte to be transferred to the Host

1. Typical (Zero Stroke Seek) 7.32 ms [3]*

2. Typical (Av er age Seek) 16.84 ms [3]

3. Maximum (Full Stroke Seek) 31.38 ms [2]

b. Single Sector Read and Transfer of data to Host (time from receipt of last byte of the CDB to the request

for a status byte transfer to Host) [7].

1. Typical (Zero Stroke Seek) 7.42 ms [3]

2. Typical (Av er age Seek) 16.95 ms [3]

3. Maximum (Full Stroke Seek) 31.49 ms [2]

5.2.4 Write data command execution time [4]

(512 byte sector size, without disconnect and with read look ahead disabled.) Latency time is included.

a. From CDB reception to the request f or the first b yte of write data from the Host.

1. Typical 1.49 ms 2. Maximum 1.61 ms

b. Single Sector Write and Data Transfer from Host [7] [6]

(Time from receipt of the last byte of the CDB to the request for a completion status transf er to the Host)

1. Typical (Zero Stroke Seek) 7.72 ms [3]

2. Typical (Av er age Seek) 17.10 ms [3]

3. Maximum (Full Stroke Seek) 31.93 ms [2]

*[ ] All notes are listed in Section 5.3.1.

10 Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F ______________________________________________________________________________________

5.3 Generalized performance characteristics

Minimum Sector Interleave 1 to 1 Data Buffer To/From Disc Media

Data transfer rate (< 1 sector) - 512 Byte Sector Min. [4]* 4.33 MByte/sec

Avg. [4] 6.15 MByte/sec Max. [4] 7.63 MByte/sec

Data Buffer To/From Disc Media

Data Transfer Rate (< 1 T r ac k) - 512 Byte Sector

Min. [4] 3.64 MByte/sec divided by (Interleave Factor) Avg. [4] 5.16 MByte/sec divided by (Interleave F actor) Max. [4] 6.41 Mbyte/sec divided by (Interleav e Factor)

SCSI Interface Data Transfer Rate (Asynchronous) [5]

ST15230N ST15230ND

-Maximum Instantaneous 5.2 MBytes/sec [9]* 3.3 MBytes/sec

-Maximum A v erage 3.1 MBytes/sec [11] 2.4 MBytes/sec

Sector Sizes 512 user data blocks (default)

Variable (256 to 4096 bytes per sector) in even number of bytes per sector. If n (number of bytes per sector) is odd, then n-1 will be used.

Synchronous T ransfer Rate

From 1.25 MByte/sec to 10.0 MBytes/sec (See section 11.5.) Read/Write consecutive sectors on a track Yes Flaw reallocation performance impact (For fla ws reallocated using the spare Negligible

sectors per track reallocation scheme.) [10] Flaw reallocation performance impact (For fla ws reallocated using the spare Negligible

sectors per cylinder reallocation scheme.) [10] Flaw reallocation performance impact (For flaws reallocated using the spare trac ks 35 ms (typical)

per volume reallocation scheme.) Overhead time for head switch (512 byte sectors) 1 ms Overhead time for one trac k cylinder switch <3 ms Typical Aver age rotational latency 5.54 ms * [ ] All notes are listed in Section 5.3.1.

Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F 11 ______________________________________________________________________________________

5.3.1 Notes for sections 5.2 and 5.3.

[1] Execution time measured from receipt of the last Byte of the Command Descriptor Block (CDB) to the

request for a Status Byte Transfer to the Initiator (excluding connect/disconnect).

[2] Maximum times are specified over the worst case conditions of temperature, v oltage margins and driv e

orientation. When comparing specified access times, care should be taken to distinguish between typical access times and maximum access times. The best comparison is obtained by system benchmark tests conducted under identical conditions. Maximum times do not include error reco v ery.

[3] Typical Access times are measured under nominal conditions of temperature, voltage, and horizontal

orientation as measured on a representative sample of drives. [4] Assumes no errors and no sector has been relocated. [5] Rate measured from the start of the first sector transfer to or from the Host. [6] Assumes the Initiator immediately sends Write Data to the drive when requested. [7] Command execution requires a data tr ansfer phase (data to or from the disc media). Assumes the initia-

tor is instantly ready to send/receive the data when the drive generates first request for a data byte

transfer, and assumes an average data transfer rate between the drive and the Initiator as specified in

section 5.3. [8] All performance characteristics assume that automatic adaptive temperature compensation is not in

process when the SCSI command is received. The following par ag raphs give highlights of thermal cali-

bration operation.

a. At spin-up, all heads are calibrated on the outer and inner diameter calibration tr ac ks.

b. A timed calibration occurs 1 minute after spin-up, and every 10 minutes thereafter. During these

timed calibrations, the firmware alternates between the inner and outer diameter calibration tracks. For example, all heads are calibrated on the inner track, then 10 minutes later all heads are calibrated on the outer track. Automatic adaptive temperature calibration does not interrupt SCSI commands being executed.

c. If automatic adaptive thermal calibration is in process when the drive receives a SCSI command, the

drive queues the command until the compensation for the specific head being compensated completes. When compensation completes f or the specific head being compensated, the drive e xecutes the first queued command. When execution of the first queued command completes, the drive continues compensation for the remaining head(s). The abov e procedure contin ues until the drive completes compensation for all heads.

d. When a timed calibration comes due, the drive postpones the calibration until the drive has been idle

for 25 to 50 milliseconds.

e. When the drive receives a Write command, the drive perf orms a single head calibration if a calibra-

tion has been delayed f or 1 to 5 minutes. The driv e performs an uninterruptible calibration of all heads if the calibration has been delayed more than 5 minutes .

f. The drive preforms a calibration of all heads prior to the first retr y of any media error if a timed

calibration has been delayed f or o v er one minute . g. Automatic adaptive temperature compensation tak es less than 0.1% of b us time. h. Automatic adaptive temperature compensation occurs at times other than mentioned above, but

should be transparent to the user (e.g., during execution of Format, Rezero, and Reassign Block

commands). i. A rezero command can be used to reset the Automatic adaptive temperature compensation timer

back to start so that the host can know when the interruption for timed thermal compensation will

occur.

[9] Assumes system ability to support 5.2 Mb/s and no cable loss. [10]Simulated. [11]Assumes Typical host delays and cable losses.

_________ *SCSI Interface commands described in SCSI Interface Manual 77738479.

12 Product Manual - Hawk 4 Famil y SCSI-2 (Volume 1), Rev. F ______________________________________________________________________________________

5.4 Start/stop time

After DC power has been applied, the drive becomes ready within 25 seconds if the Motor Start Option is disabled (i.e. the motor starts as soon as the power has been applied). During this time the drive responds to some commands over the SCSI interface* in less than 3 seconds. Stop time is 20 seconds from removal of DC power .

If the Motor Start Option is enabled the internal controller accepts the commands listed in the SCSI Interface Product Manual* less than 3 seconds after DC power has been applied. After the Motor Start Command has been received the drive becomes ready for normal operations within 25 seconds . The Motor Start Command can also be used to command the drive to stop the spindle*.

There is no power control switch on the drive .

5.5 Prefetch/multi-segmented cache control

The drive provides prefetch (read look-ahead) and multi-segmented cache control algorithms that in many cases can enhance system performance. “Cache” as used herein refers to the drive buffer storage space when it is used in “cache” oper ations. To select prefetch and cache features the host sends the Mode Select command with the proper values in the applicable bytes in Mode Page 08h*. Prefetch and cache operation are independent features from the standpoint that each is enabled and disab led independently via the Mode Select command. Ho wev er, in actual operation the pref etch feature overlaps cache oper ation somewhat as is noted in sections 5.5.1 and 5.5.2.

All default cache and prefetch Mode par ameter values (Mode Page 08h) for standard OEM versions of this drive family are giv en in Tables 11.3.2-1 through 11.3.2-4.

5.5.1 Cache operation

In general, 448 Kbytes of the 512 Kbytes of ph ysical buff er space in the driv e can be used as storage space for cache operations. The buffer can be divided into logical segments (Mode Select P age 08h, byte 13) from which data is read and to which data is written. The drive maintains a table of logical block disk medium addresses of the data stored in each segment of the buffer. If cache operation is enabled (RCD bit = 0 in Mode Page 08h, byte 2, bit 0. See SCSI Interface Product Manual*), data requested by the host with a Read command is retrieved from the buffer (if it is there), before any disc access is initiated. If cache operation is not enabled, the buff er (still segmented with required number of segments) is still used, but only as circular buffer segments during disc medium read operations (disregarding Prefetch operation f or the moment). That is, the drive does not check in the buffer segments for the requested read data, but goes directly to the medium to retrieve it. The retriev ed data merely passes through some buff er segment on the way to the host. On a cache "miss", all data transfers to the host are in accordance with “buffer-full” ratio rules. On a cache

"hit" the drive ignores the "buffer full" r atio rules. See explanations associated with Mode page 02h (discon-

nect/reconnect control) in the SCSI Interface Product Manual*. The following is a simplified description of a read operation with cache operation enab led: Case A - A Read command is received and the first logical block (LB) is already in cache:

1. Drive transfers to the initiator the first LB requested plus all subsequent contiguous LB’s that are already in the cache. This data may be in multiple segments.

2. When the requested LB is reached that is not in any cache segment, the drive fetches it and any remaining requested LB’s from the disc and puts them in a segment of the cache. The driv e transfers the remaining requested LB’s from the cache to the host in accordance with the disconnect/reconnect specification mentioned above.

3. If the prefetch feature is enab led, ref er to section 5.5.2 f or oper ation from this point.

_________ *SCSI Interface Product Manual P/N 77738479.

Product Manual - ST15230 Family SCSI-2 (Volume 1), Rev. F 13 ______________________________________________________________________________________

Case B - A Read command requests data, the first LB of which is not in any segment of the cache:

1. The drive fetches the requested LB’ s from the disc and transf ers them into a segment, and from there to

the host in accordance with the disconnect/reconnect specification referred to in case A.

2. If the prefetch feature is enab led, ref er to section 5.5.2 f or operation from this point.

Each buffer segment is actually a self-contained circular stor age (wraparound occurs), the length of which is an integer number of disc medium sectors. The wraparounds capability of the individual segments greatly enhances the buffer’s overall performance as a cache storage, allowing a wide range of user selectable configurations, which includes their use in the prefetch operation (if enab led), e ven when cache operation is disabled (see section 5.5.2). The the

size

can not be directly selected. specification. The siz e in Kbytes of each segment is reported by the Mode Sense command page 08h, bytes 14 and 15. If a size specification is sent by the host in a Mode Select command (bytes 14 and 15) no new segment size is set up by the drive, and if the “STRICT” bit in Mode page 00h (byte 2, bit 1) is set to one, the drive responds as it does for any attempt to change unchangeab le parameters (see SCSI I/O Product Manual*). The ST15230 family of drives supports operation of any integer number of segments from 1 to 16.

5.5.2 Prefetch operation

If the Prefetch feature is enab led, data in contiguous logical blocks on the disc immediately be yond that which was requested by a Read command can be retriev ed and stored in the buff er for immediate transf er from the buffer to the host on subsequent Read commands that request those logical blocks (this is true even if “cache” operation is disabled). Though the prefetch operation uses the buffer as a “cache”, finding the requested data in the buffer is a prefetch “hit”, not a “cache” operation “hit”. Prefetch is enabled using Mode Select page 08h, byte 12, bit 5 (Disable Read Ahead - DRA bit). DRA bit = 0 enables prefetch. Since data that is prefetched replaces data already in some buff er segment(s), the host can limit the amount of prefetch data to optimize system performance. The max prefetch field (b ytes 8 and 9 of Mode parameters page 08h) limits the amount of prefetch. The drive does not use the prefetch "ceiling" field (b ytes 10 and 11).

number

Size

of segments may be selected using the Mode Select command, but

is selected only as a by-product of selecting the segment

number

During a prefetch operation, the drive crosses a cylinder boundary to fetch more data (DISC) bit is set to one in bit 4 of byte 2 of Mode parameters page 08h.

Whenever pref etch (read look-ahead) is enabled (enab led by DRA = 0), it operates under the control of ARLA (Adaptive Read Look-Ahead). If the host uses software interleave, ARLA enables prefetch of contiguous blocks from the disk when it senses that a prefetch "hit" will lik ely occur, even if two consecutive read operations were not for physically contiguous blocks of data (e.g. "software inter leave"). ARLA disables prefetch when it decides that a prefetch "hit" will not likely occur . If the host is not using software interleave, and if two sequential read operations are not for contiguous blocks of data, ARLA disables prefetch, but as long as sequential read operations request contiguous blocks of data, ARLA k eeps prefetch enab led.

__________ *SCSI Interface Product Manual, P/N 77738479.

only

if the Discontinuity

+ 47 hidden pages