Fujitsu MAS3184NC/NP User manual

C141-E185-01EN
MAS3735NC/NP
MAS3367NC/NP
MAS3184NC/NP
DISK DRIVES
PRODUCT/MAINTENANCE MANUAL

C141-E185
FOR SAFE OPERATION
Handling of This manual
This manual contains important information for using this product. Read thoroughly before using the
product. Use this product only after thoroughly reading and understanding especially the section Important
Alert Items” in this manual. Keep this manual handy, and keep it carefully.
FUJITSU makes every effort to prevent users and bystanders from being injured or from suffering damage
to their property. Use the product according to this manual.
IMPORTANT NOTE TO USERS
READ THE ENTIRE MANUAL CAREFULLY BEFORE USING THIS PRODUCT.
INCORRECT USE OF THE PRODUCT MAY RESULT IN INJURY OR DAMAGE
TO USERS, BYSTANDERS OR PROPERTY.
While FUJITSU has sought to ensure the accuracy of all information in this manual, FUJITSU assumes no
liability to any party for any damage caused by any error or omission contained in this manual, its updates
or supplements, whether such errors or omissions result from negligence, accident, or any other cause. In
addition, FUJITSU assumes no liability with respect to the application or use of any porduct or system in
accordance with the descriptions or instructions contained herein; including any liability for incidental or
consequential damages arising therefrom.
FUJTSU DISCLAIMS ALL WARRANTIES REGARDING THE INFORMATION CONTAINED
HEREIN, WHETHER EXPRESSED, IMPLIED, OR STATUTORY.
FUJITSU reserves the right to make changes to any products described herein without further notice and
without obligation.
This product is designed and manufactured for use in standard applications such as office work, personal
devices and household appliances. This product is not intended for special uses (atomic controls,
aeronautic or space systems, mass transport vehicle operating controls, medical devices for life support, or
weapons firing controls) where particularly high reliability requirements exist, where the pertinent levels of
safety are not guaranteed, or where a failure or operational error could threaten a life or cause a physical
injury (hereafter referred to as "mission-critical" use). Customers considering the use of these products for
mission-critical applications must have safety-assurance measures in place beforehand. Moreover, they are
requested to consult our sales representative before embarking on such specialized use.
The contents of this manual may be revised without prior notice.
The contents of this manual shall not be disclosed in any way or reproduced in any media without the
express written permission of Fujitsu Limited.
All Right Reserved, Copyright © FUJITSU LIMITED 2002

C141-E185 i
REVISION RECORD
Edition Date published Revised contents
01 November, 2002
Specification No.: C141-E185-**EN

ii C141-E185
Related Standards
roduct specifications and functions described in this manual comply with the following ANSI
(*1) standards.
Document number Title
T10/1236D Rev.20
[NCITS.351:2001]
SCSI rimary Commands-2 (S C-2)
T10/996D Rev.8c
[NCITS.306:1998]
SCSI-3 Block Commands (SBC)
T10/1157D Rev.20 SCSI Architecture Model-2 (SAM-2)
T10/1365D Rev.7 SCSI arallel Interface-4 (S I-4)
*1 ANSI = American National Standard Institute
In case of conflict between this manual and any referenced document, this manual takes
precedence.

C141-E185 iii
PREFACE
This manual describes the MAS3735NC/N , MAS3367NC/N and MAS3184NC/N (hereafter, MAS
series), 3.5 type fixed disk drives with an embedded SCSI controller.
This manual details the specifications and functions of the above disk drive, and gives the requirements and
procedures for installing it into a host computer system.
This manual is written for users who have a basic understanding of fixed disk drives and their use in
computer systems. The MANUAL ORGANIZATION section describes organization and scope of this
manual. The need arises, use the other manuals.
OVERVIEW OF MANUAL
This manual consists of the following eight chapters:
CHAPTER 1 GENERAL DESCRIPTION
This chapter introduces the MAS series disk drives and discusses their standard features, hardware, and
system configuration.
CHAPTER 2 SPECIFICATIONS
This chapter gives detailed specifications of the MAS series disk drives and their installation environment.
CHAPTER 3 DATA FORMAT
This chapter describes the data structure of the disk, the address method, and what to do about media
defects.
CHAPTER INSTALLATION REQUIREMENTS
This chapter describes the basic physical and electrical requirements for installing MAS series disk drives.
CHAPTER 5 INSTALLATION
This chapter explains how to install MAS series disk drives. It includes the notice and procedures for
setting device number and operation modes, mounting the disk drive, connecting the cables, and confirming
drive operation.
CHAPTER 6 DIAGNOSIS AND MAINTENANCE
This chapter describes the automatic diagnosis, and maintenance of MAS series disk drive. This chapter
also describes diagnostic methods for operation check and the basics of troubleshooting the disk drives.
CHAPTER 7 ERROR ANALYSIS
This chapter describes in details how collect the information for error analysis and how analyze collected
error information.
APPENDIX A TO B
The appendixes give supplementary information, including a list of setting items and the signal assignments
of interface connector.

iv C141-E185
CONVENTIONS FOR ALERT MESSAGES
This manual uses the following conventions for alerts to prevent physical or property damages to users or
by standards.
CAUTION This indicates that either minor or moderate
personal injury may occur if the user does not
perform the procedure correctly.
NOTICE This indicates that inconvenience to the user
such as damages to the product, equipment, data,
and/or other property may occur if the user does
not pay attention or perform the procedure
correctly.
IMPORTANT This indicates information that the helps the user
use the product more effectively.
CONVENTIONS USED IN THIS MANUAL
The MAS3735NC/N , MAS3367NC/N and MAS3184NC/N disk drives are described as "the intelligent
disk drive (IDD)", "the drive" or "the device" in this manual.
Decimal number is represented normally.
Hexadecimal number is represented as X'17B9', 17B9h or 17B9H.
Binary number is represented as "010".
ATTENTION
lease forward any comments you may have regarding this manual.
To make this manual easier for users to understand, opinions from readers are needed. lease write your
opinions or requests on the Comment at the back of this manual and forward it to the address described in
the sheet.

C141-E185 v
Important Alert Items
Important Alert Messages
The important alert messages in this manual are as follows:
A hazardous situation could result in minor or moderate personal injury if the
user does not perform the procedure correctl . This alert signal also indicates
that damages to the product or other propert may occur if the user does not
perform the procedure correctl .
Task Alert message Page
Data loss
For MAS series, Reed Solomon codes are applied for their ECC.
The sector-data is diided into 4 interlea ing sectors, and ECC is
performed in each sector where the maximum number of errors
(up to 5 byte) can be corrected. [Total maximum byte: 5 byte
×
4
( interleae) = 20 byte]
If the error of read sector keeps allowable error byte number,
correction is performed.
Howe er, if error byte exceeds its allowable number, correction
may not be performed properly.
Hot temperature
To pre ent injury, do not handle the dri e until after the de ice has
cooled sufficiently after turning off the power. The DE and LSI
become hot during operation and remain hot immediately after
turning off the power.
Data loss
1. The user must not change the setting of terminals not described
in this section. Do not change setting status set at factory
shipment.
2. Do not change the setting of terminals except following setting
pins during the power is turned on.
• Write protect: CN2 9-10 (NP model only)
3. To short the setting terminal, use the short plug attached when
the de ice is shipped from the factory.
2-5
5-1
5-5
Mounting Installation
Damage
1. Make sure that system power is off before connecting or
disconnecting cables.
2. Do not connect or disconnect cables when power is on.
(except NC model)
5-12

vi C141-E185
Task Alert message age
Damage
1. Be careful of the insertion orientation of the SCSI connectors.
With the system in which terminating resistor power is supplied
ia the SCSI cable, if the power is turned on, the o ercurrent
protection fuse of the terminating resistor power supplier may
be blown or the cable may be burnt if o ercurrent protection is
not pro ided.
When the recommended parts listed in Table 4.2 are used,
inserting the cables in the wrong direction can be pre ented.
2. To connect SCSI de ices, be careful of the connection position
of the cable. Check that the SCSI de ice with the terminating
resistor is the last de ice connected to the cable.
5-12
Mounting Installation
Data loss
When the SEND DIAGNOSTIC command terminates with the
CHECK CONDITION status, the INIT must collect the error
information using the REQUEST SENSE command. The RECEIVE
DIAGNOSTIC RESULTS command cannot read out the error
information detected in the self-diagnostics.
Caution
1. To a oid shocks, turn off the power before connecting or
disconnecting a cable, connector, or plug.
2. To a oid injury, do not touch the mechanical assembly during
disk dri e operation.
3. Do not use sol ents to clean the disk dri e.
Caution
1. Always ground yourself with a wrist strap connected to ground
before handling. ESD (Electrostatics Discharge) may cause
the damage to the de ice.
2. To pre ent electrical damage to the disk dri e, turn the power
off before connecting or disconnecting a cable, connector, or
plug.
3. Do not remo e a PCA. This operation is required to pre ent
unexpected or unpredictable operation.
4. Do not use a conducti e cleaner to clean a disk dri e assembly.
5. Ribbon cables are marked with a colored line. Connect the
ribbon cable to a cable connector with the colored wire
connected to pin 1.
Damage
Ne er open the disk enclosure in the field. Opening the disk
enclosure may cause an irreparable fault.
Data loss
Sa e data stored on the disk dri e before requesting repair. Fujitsu
does not assume responsibility if data is destroyed during ser icing
or repair.
6-4
6-5
6-6
6-6
6-15
6-7

C141-E185 vii
MANUAL ORGANIZATION
RODUCT/
MAINTENANCE
MANUAL
(This manual)
1. General Description
2. Specifications
3. Data Format
4. Installation Requirements
5. Installation
6. Diagnostics and Maintenance
7. Error Analysis
SCSI hysical
Interface
Specifications
1. SCSI Bus
2. SCSI Message
3. SCSI Bus Error Recovery rocessing
SCSI Logical
Interface
Specifications
1. Command rocessing
2. Data Buffer Management
3. Command Specification
4. Sense Data and error Recovery rocedure
5. Disk Medium Management

This page is intentionally left blank.

C141-E185 ix
CONTENTS
page
CHAPTER 1 GENERAL DESCRIPTION ............................................................................1-1
1.1 Standard Features ..............................................................................................................1-2
1.2 Hardware Structure............................................................................................................1-6
1.3 System C nfigurati n ........................................................................................................1-9
CHAPTER 2 SPECIFICATIONS...........................................................................................2-1
2.1 Hardware Specificati ns....................................................................................................2-1
2.1.1 M del name and rder number..........................................................................................2-1
2.1.2 Functi n specificati ns......................................................................................................2-2
2.1.3 Envir nmental specificati ns ............................................................................................2-4
2.1.4 Err r rate ...........................................................................................................................2-5
2.1.5 Reliability..........................................................................................................................2-5
2.2 SCSI Functi n Specificati ns............................................................................................2-7
CHAPTER 3 DATA FORMAT...............................................................................................3-1
3.1 Data Space.........................................................................................................................3-1
3.1.1 Cylinder c nfigurati n.......................................................................................................3-1
3.1.2 Alternate spare area...........................................................................................................3-4
3.1.3 Track f rmat......................................................................................................................3-5
3.1.4 Sect r f rmat.....................................................................................................................3-7
3.1.5 F rmat capacity.................................................................................................................3-9
3.2 L gical Data Bl ck Addressing.........................................................................................3-9
3.3 Defect Management...........................................................................................................3-11
3.3.1 Defect list ..........................................................................................................................3-11
3.3.2 Alternate bl ck all cati n .................................................................................................3-11
CHAPTER 4 INSTALLATION REQUIREMENTS .............................................................4-1
4.1 M unting Requirements ....................................................................................................4-1
4.1.1 External dimensi ns ..........................................................................................................4-1
4.1.2 M unting ...........................................................................................................................4-4
4.1.3 N tes n m unting ............................................................................................................4-4
4.2 P wer Supply Requirements .............................................................................................4-8
4.3 C nnecti n Requirements..................................................................................................4-11
4.3.1 SCA2 c nnect r type 16-bit SCSI m del (NC m del) ......................................................4-11

xC141-E185
4.3.2 68 pin c nnect r type 16-bit SCSI m del (NP m del)......................................................4-13
4.3.3 Cable c nnect r requirements ...........................................................................................4-20
4.3.4 External perat r panel ( n NP m del drives nly) ..........................................................4-21
CHAPTER 5 INSTALLATION...............................................................................................5-1
5.1 N tes n Handling Drives .................................................................................................5-1
5.2 C nnecti ns.......................................................................................................................5-3
5.3 Setting Terminals ..............................................................................................................5-5
5.3.1 SCSI ID setting..................................................................................................................5-6
5.3.2 Each m de setting .............................................................................................................5-8
5.3.3 M de settings ....................................................................................................................5-10
5.4 M unting Drives................................................................................................................5-11
5.4.1 Check bef re m unting .....................................................................................................5-11
5.4.2 M unting pr cedures.........................................................................................................5-11
5.5 C nnecting Cables.............................................................................................................5-12
5.6Cnfirming Operati ns after Installati n and Preparati n fr Use....................................5-13
5.6.1 C nfirming initial perati ns.............................................................................................5-13
5.6.2 Checking SCSI c nnecti n................................................................................................5-14
5.6.3 F rmatting .........................................................................................................................5-17
5.6.4 Setting parameters .............................................................................................................5-19
5.7 Dism unting Drives...........................................................................................................5-23
5.8 Spare Disk Drive ...............................................................................................................5-23
CHAPTER 6 DIAGNOSTICS AND MAINTENANCE ........................................................6-1
6.1 Diagn stics........................................................................................................................6-1
6.1.1 Self-diagn stics .................................................................................................................6-1
6.1.2 Test pr grams....................................................................................................................6-4
6.2 Maintenance Inf rmati n ..................................................................................................6-5
6.2.1 Precauti ns ........................................................................................................................6-5
6.2.2 Maintenance requirements.................................................................................................6-6
6.2.3 Maintenance levels............................................................................................................6-8
6.2.4 Revisi n numbers..............................................................................................................6-9
6.2.5 T ls and test equipment...................................................................................................6-10
6.2.6 Tests ..................................................................................................................................6-10
6.3 Operati n Check................................................................................................................6-12
6.3.1 Initial seek perati n check...............................................................................................6-12
6.3.2 Operati n test ....................................................................................................................6-12

C141-E185 xi
6.3.3 Diagn stic test...................................................................................................................6-12
6.4 Tr ublesh ting Pr cedures..............................................................................................6-13
6.4.1 Outline f tr ublesh ting pr cedures ..............................................................................6-13
6.4.2 Tr ublesh ting with disk drive replacement in the field .................................................6-13
6.4.3 Tr ublesh ting at the repair site......................................................................................6-15
6.4.4 Tr ublesh ting with parts replacement in the fact ry .....................................................6-16
6.4.5 Finding p ssibly faulty parts .............................................................................................6-16
CHAPTER 7 ERROR ANALYSIS .........................................................................................7-1
7.1 Err r Analysis Inf rmati n C llecti n ..............................................................................7-1
7.1.1 Sense data..........................................................................................................................7-1
7.1.2 Sense key, sense c de, and subsense c de ........................................................................7-1
7.2 Sense Data Analysis ..........................................................................................................7-3
7.2.1 Err r inf rmati n indicated with sense data......................................................................7-3
7.2.2 Sense data (3-0C-03), (4-40-xx), (4-44-xx), and (4-C4-xx) ..............................................7-4
7.2.3 Sense data (1-1x-xx), (3-1x-xx) and (E-1D-00): Disk read err r ....................................7-4
7.2.4 Sense data (5-2x-xx), (5-3D-00), (5-90-00), (B-47-xx), (B-49-00),
(B-4D-xx) and (B-4E-00): SCSI interface err r...............................................................7-4
APPENDIX A SETTING TERMINALS ..................................................................................A-1
A.1 Setting Terminals ( n NP m del nly)..............................................................................A-2
APPENDIX B CONNECTOR SIGNAL ALLOCATION .......................................................B-1
B.1 SCSI C nnect r Signal All cati n: SCA2 type LVD 16-bit SCSI...................................B-2
B.2 SCSI C nnect r Signal All cati n: 68 pin type LVD 16-bit SCSI ..................................B-3
INDEX ........................................................................................................................................IN-1

xii C141-E185
FIGURES
page
Figure 1.1 NC m del drives uter view.................................................................................................1-6
Figure 1.2 NP m del drives uter view .................................................................................................1-6
Figure 1.3 Disk/head c nfigurati n........................................................................................................1-7
Figure 1.4 System c nfigurati n ............................................................................................................1-9
Figure 3.1 Cylinder c nfigurati n..........................................................................................................3-2
Figure 3.2 Spare area in cell ..................................................................................................................3-5
Figure 3.3 Alternate cylinder .................................................................................................................3-5
Figure 3.4 Track f rmat.........................................................................................................................3-6
Figure 3.5 Track skew/head skew..........................................................................................................3-7
Figure 3.6 Sect r f rmat ........................................................................................................................3-7
Figure 3.7 Alternate bl ck all cati n by FORMAT UNIT c mmand .................................................3-13
Figure 3.8 Alternate bl ck all cati n by REASSIGN BLOCKS c mmand ........................................3-14
Figure 4.1 NC external dimensi ns........................................................................................................4-2
Figure 4.2 NP external dimensi ns ........................................................................................................4-3
Figure 4.3 IDD rientati ns ...................................................................................................................4-4
Figure 4.4 M unting frame structure .....................................................................................................4-5
Figure 4.5 Limitati n f side-m unting .................................................................................................4-5
Figure 4.6 Surface temperature measurement p ints .............................................................................4-6
Figure 4.7 Service clearance area ..........................................................................................................4-7
Figure 4.8 Spin-up current wavef rm (+12 VDC) .................................................................................4-8
Figure 4.9 P wer n/ ff sequence (1)....................................................................................................4-8
Figure 4.10 P wer n/ ff sequence (2)....................................................................................................4-9
Figure 4.11 P wer n/ ff sequence (3)....................................................................................................4-9
Figure 4.12 AC n ise filter (rec mmended) ..........................................................................................4-11
Figure 4.13 NC c nnect rs l cati n ......................................................................................................4-11
Figure 4.14 SCA2 type 16-bit SCSI c nnect r ......................................................................................4-12
Figure 4.15 NP c nnect rs and terminals l cati n ................................................................................4-13
Figure 4.16 68 pin type 16-bit SCSI interface c nnect r.......................................................................4-14
Figure 4.17 P wer supply c nnect r (68 pin type 16-bit SCSI) ............................................................4-14
Figure 4.18 External perat r panel c nnect r (CN1)...........................................................................4-15
Figure 4.19 External perat r panel c nnect r (CN2)...........................................................................4-15

C141-E185 xiii
Figure 4.20 16-bit SCSI ID external input .............................................................................................4-16
Figure 4.21 Output signal f r external LED ..........................................................................................4-18
Figure 4.22 SCSI cables c nnecti n ......................................................................................................4-19
Figure 4.23 External perat r panel circuit example .............................................................................4-21
Figure 5.1 SCSI bus c nnecti ns ..........................................................................................................5-4
Figure 5.2 Setting terminals l cati n ( n NP m dels nly) ...................................................................5-5
Figure 5.3 CN2 setting terminal ( n NP m dels nly)...........................................................................5-6
Figure 5.4 Checking the SCSI c nnecti n (A).....................................................................................5-15
Figure 5.5 Checking the SCSI c nnecti n (B) .....................................................................................5-16
Figure 6.1 Revisi n label .......................................................................................................................6-9
Figure 6.2 Indicating revisi n numbers................................................................................................6-10
Figure 6.3 Test fl wchart.....................................................................................................................6-11
Figure 7.1 F rmat f extended sense data..............................................................................................7-2

xiv C141-E185
TABLES
page
Table 2.1 M del names and rder numbers..............................................................................................2-1
Table 2.2 Functi n specificati ns .............................................................................................................2-2
Table 2.3 Envir nmental/p wer requirements..........................................................................................2-4
Table 2.4 SCSI functi n specificati ns.....................................................................................................2-7
Table 3.1 Z ne lay ut and track capacity .................................................................................................3-3
Table 3.4 F rmat capacity ........................................................................................................................3-9
Table 4.1 Surface temperature check p int...............................................................................................4-6
Table 4.2 Rec mmended c mp nents f r c nnecti n ............................................................................4-20
Table 5.1 SCSI ID setting.........................................................................................................................5-7
Table 5.2 Setting SCSI terminat r p wer supply (NP m del)..................................................................5-8
Table 5.3 M t r start m de setting...........................................................................................................5-8
Table 5.4 Write pr tect setting (NP m del)..............................................................................................5-9
Table 5.5 Setting f the SCSI interface perati n m de (NP m del).......................................................5-9
Table 5.6 Setting the bus width f the SCSI interface (NP m del)..........................................................5-9
Table 5.7 Default m de settings (by CHANGE DEFINITION c mmand) ............................................5-10
Table 5.8 Setting check list (NP m del nly) .........................................................................................5-11
Table 6.1 Self-diagn stic functi ns ..........................................................................................................6-1
Table 6.2 System-level field tr ublesh ting .........................................................................................6-14
Table 6.3 Disk drive tr ublesh ting .....................................................................................................6-15
Table 7.1 Definiti n f sense data ............................................................................................................7-3
Table A.1 CN2 setting terminal ( n NP m del drives nly).................................................................A-2
Table B.1 SCSI c nnect r (SCA2 type LVD 16-bit SCSI): CN1 ...........................................................B-2
Table B.2 SCSI c nnect r (68 pin type LVD 16-bit SCSI): CN1...........................................................B-3

C141-E185 1-1
CHAPTER 1 GENERAL DESCRIPTION
1.1 Standard Features
1.2 Hardware Structure
1.3 Syste Configuration
This chapter describes the feature and configuration of the MAS series intelligent disk drives IDD).
IDDs are high performance large capacity 3.5 type fixed disk drives with an embedded SCSI controller.
The MAS series disk drives support the Small Computer System Interface SCSI) as described in the ANSI
SCSI SPI-4 [T10/1365D Rev.7] to the extent described in this manual.
The flexibility and expandability of the SCSI, as well as the powerful command set of the IDD, allow the
user to construct a high-performance reliable disk subsystem with large storage capacity.
The data format can be changed from the format at factory shipment by reinitializing with the user's system.
Refer to SCSI Logical Interface Specifications for details.

1-2 C141-E185
1.1 Standard Features
1) Compactness
Since the SCSI controller circuit is embedded in the standard 3.5 type fixed disk drive form factor,
the IDD is extremely compact. The IDD can be connected directly to the SCSI bus of the host
system.
2) SCSI standard
The IDD provides not only SCSI basic functions but also the following features:
• Arbitration
• Disconnection/Reconnection
• Data bus parity
The SCSI commands can manipulate data through logical block addressing regardless of the
physical characteristics of the disk drive. This allows software to accommodate future expansion
of system functions.
3) 8-bit SCSI/16-bit SCSI
The IDD has 16-bit data bus width 16-bit SCSI), which have the wide transfer function suitable
for SCSI-2. 8-bit data bus is available only with NP model.
See subsection 5.3.2 for details of the bus width setting.
For the ultra SCSI model, number of connectable SCSI devices on the same SCSI bus is varied as
follows.
• 8-bit SCSI: 8 drives max. option for NP model)
• 16-bit SCSI: 16 drives max.
4) High speed data transfer
Such a high data transfer rate on the SCSI bus can be useful with the large capacity buffer in the
IDD.
• 8-bit SCSI: The data transfer rate on the SCSI bus is 40 MB/s maximum at the
synchronous mode.
• 16-bit SCSI: The data transfer rate on the SCSI bus is 320 MB/s maximum at the paced
transfer synchronous mode.

C141-E185 1-3
Note:
The maximum data transfer rate in asynchronous mode may be limited by the response time of
initiator and the length of SCS bus length. The maximum data transfer rate in synchronous
mode may be limited by the cable length, transmission characteristics of the SCS bus and the
connected SCS device number.
(5) Continuous block processing
The addressing method of data blocks is logical block address. The initiator can access data by
specifying block number in a logically continuous data space without concerning the physical
structure of the track or cylinder boundaries.
The continuous processing up to [64K-1] blocks in a command can be achieved, and DD can perform
continuous read/write operation when processing data blocks on several tracks or cylinder.
(6) Programmable multi-segment data buffer
The data buffer is 8M bytes. Data is transferred between SCS bus and disk media through this
data buffer. This feature provides the suitable usage environment for users.
Since the initiator can control the disconnect/reconnect timing on the SCS bus by specifying the
condition of stored data to the data buffer or empty condition of the data buffer, the initiator can
perform the effective input/output operations with utilizing high data transfer capability of the
SCS bus regardless of actual data transfer rate of the disk drive.
(7) Cache feature
After executing the READ command, the DD reads automatically and stores (prefetches) the
subsequent data blocks into the data buffer (Read-ahead caching).
The high speed sequential data access can be achieved by transferring the data from the data buffer
without reaccessing the disk in case the subsequent command requests the prefetched data blocks.
The write cache feature is supported. When this feature is enabled, the status report is issued without
waiting for completion of write processing to disk media, thereby enabling high speed write processing.
IMPORTANT
When Write cache is enabled, you should ensure that the cashed
data is surely flushed to the disc media before you turn off the drive's
power.
To ensure it, you should issue either the SYNCH ONIZE CASHE
command or the STOP UNIT command with specifying “0” to the
Immed bit and then confirm that the command is surely terminated
with the GOOD STATUS.

1-4 C141-E185
(8) Command queuing feature
The DD can queue maximum 128 commands, and optimizes the issuing order of queued
commands by the reordering function. This feature realizes the high speed processing.
(9) Reserve and release functions
The DD can be accessed exclusively in the multi-host or multi-initiator environment by using the
reserve and release functions.
(10) Error recovery
The DD can try to recover from errors in SCS bus or the disk drive using its powerful retry
processing. f a recoverable data check occurs, error-free data can be transferred to the initiator
after being corrected in the data buffer. The initiator software is released from the complicated
error recover processing by these error recovery functions of the DD.
(11) Automatic alternate block reassignment
f a defective data block is detected during read or write the DD can automatically reassign its
alternate data block.
(12) Programmable data block length
Data can be accessed in fixed-block length units. The data block length is programmable, and can
be specified at initializing with a multiple of four within the range of 512 to 528 bytes.
IMPORTANT
Error rate increase
1. The drive format at factory shipment is generally 512 byte.
2. The ecoverable Error of the drive might increase when the
format would be modified from 512 bytes to the following values:
516 bytes, 520 bytes, 524 bytes, 528 bytes.
3. The ecoverable Error referred to here is sense data (1-13-xx).
(13) Defective block slipping
A logical data block can be reallocated in a physical sequence by slipping the defective data block
at formatting. This results in high speed contiguous data block processing without a revolution
delay due to defective data block.
(14) High speed positioning
A rotary voice coil motor achieves fast positioning.