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Revision status summary sheet
RevisionDateWriter/EngineerSheets Affected
A01/09/98L. Newman/B. RatheAll
This manual is volume 1 of a two-volume document with the SCSI interface information in the volume 2
SCSI Interface Product Manual
If you need SCSI interface information, order the volume 2
This manual describes Seagate Technology®, Inc. Elite 47™ disc drives.
Elite 47 drives support the small computer system interface (SCSI) as described in the ANSI SCSI, SCSI-2,
and SCSI-3 (Fast-20 or Ultra SCSI) interface specifications to the extent described in this manual. The
Interface Product Manual
other families of Seagate drives.
From this point on in this product manual the reference to Eli te 47 models is referred to as “the drive” (unless
references to individual models are necessary).
(part number 77738479) describes general SCSI interface characteristics of this and
SCSI
Figure 1.Elite 47 disc drive
Elite 47 Product Manual, Rev. A3
2.0Applicable standards and reference documentation
The drive is a system peripheral developed to the highest standards of design and construction. The dr ive
depends on its host equipment to provide adequ ate power and environment to achieve optimum performance
and compliance with applicable i ndustry and government regulations. Special attention must be given in the
areas of safety, power distr ibution, shieldin g, audible no ise cont rol, and temperature regulation. Also, the drive
must be securely mounted to guarantee the specified performance characteristics.
2.1Standards
The Elite 47 family complies with Seagate standards as noted in the appropr iate sections of this manual and
the Seagate
The Elite 47 disc drive is a UL recog nized component per UL1 950, CSA cert ified to CSA C22.2 No. 950-789,
and VDE certified to VDE 0805 and EN 60950.
2.1.1Electromagnetic compatibility
The drive, as delivered, is designed f or s ystem integr ation and installation into a suitable enclosure prior to use.
As such, the drive is supplied as a su bassembly and is no t subject to S ubpar t B of Part 15 of t he FCC Ru les
and Regulations nor the Radio Interference Regulations of the Canadian Department of Communications.
The physical design characteristics of the dr ive serve to m inimize radiation when i nstal led in an enc losure 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 Depar tment of Communications when proper ly packaged. However, it is the
user’s responsibility to assure that the drive meets the appropriate EMI requiremen ts in their system. Shielded
I/O cables may be required if the enclosure does not provide adeq uate shielding. If the I/O cables are external
to the enclosure, shielded cables should be used, with the shields grounded both to the enclosure and to the
host controller.
SCSI Interface Product Manual
(volume 2), part number 77738479.
2.1.1.1Electromagnetic susceptibility
As a component assem bly, the drive is not required to me et any suscep tibility perform ance requi rements. It is
the responsibility of those integrating the dri ve within their systems to perform t hose t ests req uired a nd des i gn
their system to ensure that equipm ent operating in the same system as the drive or external to the system
does not adversely affect the perf ormance of the drive. S ee Section 5.1.1 and Table 1, DC power requirements.
2.2Electromagnetic compliance
Seagate uses an independen t laboratory to confirm com pliance to the directives/standard(s) for CE Marking
and C-Tick Marking. 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 PowerPC microprocessors
• 3.5-inch floppy disc drive
• Keyboard
• Monitor/display
• Printer
• External modem
•Mouse
Although the test system with this Seagate m odel com pli es to the direct ives/standard(s), we cannot guarantee
that all systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance
and provide CE Marking and C-Tick Marking for their product.
Electromagnetic compliance for the European Union
If this model has the CE Marking it complies with the European Union requirements of the Electromagnet ic
Compatibility Directive 89/336/EEC of 03 M ay 198 9 as amended by Directive 92/31/EEC of 28 April 1992 a nd
Directive 93/68/EEC of 22 July 1993.
4Elite 47 Product Manual, Rev. A
Australian C-Ti ck
If this model has the C-Tick Marking it complies with the Australia/New Zealand Standard AS/NZS3548 1995
and meets the Electromagnetic Compatibility (EMC) Framework requirements of Australia’s Spectrum Management Agency (SMA).
ANSI small computer system interface (SCSI) document numbers:
X3.131-1994SCSI-2
X3.253-1995SCSI-3 Parallel Interface
Package Test SpecificationSeagate P/N 30190-001 (under 100 lb.)
Package Tes t Spe cificationSeagate P/N 30191-001 (over 100 lb.)
In case of conflict between this document and any referenced document, this document takes precedence.
(Volume 2)Seagate P/N 77738479
Seagate P/N 83329290
Elite 47 Product Manual, Rev. A5
3.0General description
Elite 47 drives combine magnetoresistive (MR) heads, partial response/maximum likelihood (PRML) read
channel electronics, embedded servo technology, and a SCSI-3 (Fast-20) interface to provide high performance, high capacity data storage for a variety of systems including engineering workstations, network servers, mainframes, and supercomputers.
Fast-20 (also known as Ultra SCSI) is a negotiated transfer rate. This transfer rate will occur only if your host
adapter also supports Fast-20 data transfer rates. This drive also operates at SCSI-1 and SCSI-2 data transfer
rates for backward compatibility with non-Fast-20 capable SCSI host adapters.
This manual describes the Elite 47 model ST446452W. It has a 68-pin interface connector for a 16-bit data b us.
The drive records and recovers data on 5.25-inch (133.4 mm) non-removeable discs.
The drive supports the S mall Computer System Interface (SCSI) as describ ed in the ANSI SCSI-2 interface
specifications to the extent described in this manual (volume 1), which defi nes the product perform ance characteristics of the Elite 47 family of drives, and the
77738479, which describes the general interface characteristics of this and other families of Seagate SCSI
drives.
The drive’s interface supports multiple initiators, disconnect/reconnect, self-configuring host software, and
automatic features that relieve the host from the necessity of knowing the physical characteristics of the targets
(logical block addressing is used).
The head and disc assembly (HDA) is sealed at the factory. Air circulates within the HDA through a nonreplaceable filter to maintain a contamination-free HDA environment.
SCSI Interface Product Manual
(volume 2), par t number
Refer to Figure 2 for an exploded view of the drive. This exploded view is for information only—never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads, med ia, actuator, etc.) as this
requires special facilities. The drive contains no replaceable parts. Opening the HDA voids your warranty.
Elite 47 drives use a dedicated landing zone at the innermost radius of the media to eliminate the possibi lity of
destroying or degrading data by landing in the data zone. The drive automatically goes to the landing zone
when power is removed.
An automatic shipping lock prevents potential damage to the heads and discs that results from movement during shipping and handling. The shipping lock automati cally diseng ages when power is appli ed t o the drive and
the head load process begins.
Elite 47 drives decode track 0 location data from the servo data embedded on each surface to eliminate
mechanical transducer adjustments and related relia bilit y con ce rns.
A high-performance actuator assembly with a low-inertia, balanced, pa tented, straight-arm design provides
excellent performance with minimal power dissipation.
6Elite 47 Product Manual, Rev. A
Figure 2.Elite 47 family drive
3.1Standard features
Elite 47 drives have the following standard features:
• Integrated SCSI controller
• Single-ended SCSI drivers and receivers
• 16-bit I/O data bus
• Asynchronous and synchronous data transfer protocols
• Firmware downloadable using the SCSI interface
• Programmable drive capacity
• Selectable sector size from 512 to 4,096 bytes per sector
• Programmable sector reallocation scheme
• Flawed sector reallocation at format time
• Programmable auto write and read reallocation
• Reallocation of defects on command (post format)
• Reed-Solomon error-correction code for header and data fields; can correct up to 64-bit error
• Sealed head and disc assembly (HDA)
• No preventative maintenance or adjustment required
• Dedicated head landing zone
• Embedded servo data rather than a separate servo data surface
• Self-diagnostics performed when power is applied to the drive
• 1:1 interleave
• Zone bit recording (ZBR)
• Vertical, horizontal, or top-down mounting
Elite 47 Product Manual, Rev. A7
• Dynamic spindle brake
• Active IC terminators enabled by jumper
• 4,096 Kbyte data buffer . See Section 4.5
3.2Media characteristics
The media used on the dri ve has a diamet er of approximately 5.25 i nc hes (134 mm). The aluminum subst rate
is coated with a thin film magnetic material, overcoated with a proprietary protective layer for improved durability and environmental protection.
3.3Performance
• Supports industry-standard Fast-20 SCSI interface (also called “Ultra SCSI”)
• Programmable multi-segmentable cache buffer
• 5,357 RPM spindle; average latency = 5.60 msec
• Command queuing of up to 64 commands
• Background processing of queue
• Supports start and stop commands (spindle stops spinning)
• Low audible noise for office environment
• Low power consumption
3.4Reliability
• 800,000 hour MTBF
• LSI circuitry
• Balanced low mass rotary voice coil actuator
• Incorporates industr y -standa rd Self-Monitoring, Analysis and Repor ting Technology (S.M.A.R.T.)
• Incorporates Seek To Improve Reliability algorithm (STIR)
3.5Unformatted a n d formatted capacities
Formatted capacity depends on the number of spare reallocation sectors reserved and the number of bytes per
sector. The following table shows standard OEM model capacities:
Formatted [1]Unformatted
ST44645247.0 Gbytes [2]62.6 Gbytes
Notes.
[1]Standard OEM models a re formatted to have 512-byte sectors. Users having the necessar y equipment
may modify the data block size before issuing a f ormat 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,
part number 77738479.
[2]The number of data tracks per sparing zone and the number of alternate sectors (LBAs) per sparing zone
can be determined by using the Mode Sense command and reading Mode page 03h.
3.6Programmable drive capacity
Using the Mode Select command, the drive can change its capacity to something less than maximum. See
Table 5.2.1-13 in the
SCSI Interface Product Manual
, part number 77738479 . Refer to the Parameter list block
descriptor number of blocks field. A value of zero in the number of blocks field indicat es that the dri ve will not
change the capacity it is currently formatted to have. A number in the number of blocks field that is less than
the maximum number o f LBAs chan ges the tot al drive capacity to the value in the block de scriptor num ber of
blocks field. A value greater than the maximum number of LBAs is rounded down to the maximum capacity.
3.7Factory installed accessories
Elite 47 Installation Guide
The
, part num ber 83329290, is shipped with each standard OE M drive (unless otherwise specified). A small bag of jumpers are also s hipped with the dr ive. Use these jumpers to configure the
option headers. See Section 8.1.
SCSI terminators can be enabled or disabled.
8Elite 47 Product Manual, Rev. A
3.8Options (factory installed)
All options that a cus t om er m ay request are i nc orporated during production or packaged at the manufacturing
facility before shipping. Some of the options available are:
• The capacities shown in Section 3.5. You can order other capacities by selecting other sparing schemes and
sector sizes.
• Single-unit shipping pack. The drive normally ships in bulk packaging to provide maximum protection against
transit damage. Units shipped i ndividually require additional protection as provided by the si ngle-unit shipping pack. Specify this option if you are planning to ship single units to your customers.
•The
3.9Accessories (user installed)
The following accessories are available.
• Single-unit shipping pack.
Elite 47 Installation Guide
Additional copies may be ordered.
, part number 83329290, is usually included wi th each standard OEM dr ive.
Elite 47 Product Manual, Rev. A9
4.0Performance characteristics
4.1Internal drive characteristics (transparent to user)
4.2SCSI seek performance characteristics (visible to user)
Refer to Section 9.10 and to the
SCSI Interface Product Manual
(part number 77738479 ) for additional timing
details.
4.2.1Access time
Including controller overhead
(without disconnect) [1] [4]
Drive level
ReadWrite
ms
AverageTypical [3]13.214.2
Single trackTypical [3]1.32.3
Full strokeTypical [3]28.228.2
4.2.2Format command execution time (for ≥ 512-byte sectors)
Maximum (with verify)10.0 hours
Maximum (no verify)6.0 hours
4.2.3General performance characteristi cs
Minimum sector interleave1 to 1
Data buffer data transfer rate to/from disc media (one 512-byte sector) variable with zone/cylinder:
Minimum[4]125 Mbits/sec
Maximum[4]185 Mbits/sec
SCSI interface data transfer rate (asynchronous) [5]:
Maximum instantaneous (1-byte-wide transfer rate)5. 0 Mbytes/sec [6]
Maximum instantaneous (2-byte-wide transfer rate)10. 0 Mbytes/sec [7]
Synchronous transfer rate for SCSI Fast-20 (Ultra SCSI):
16 bit data bus5.0 to 40 Mbytes/sec
[] All notes for Sections 4.2 are listed at end of Section 4.2.3.
10Elite 47 Product Manual, Rev. A
Synchronous transfer rate for fast SCSI-2:
16 bit data bus5.0 to 40 Mbytes/sec
Sector sizes:
Default512-byte data blocks
Variable in even-sector sizes512 to 4,096 bytes per sector
Read/write consecutive sectors on a trackYes
Flaw reallocation performance impact :
For flaws reallocated at format time using spare
sectors per track reallocation schemenegligible
For flaws reallocated after format time using spare
sectors per cylinder reallocation scheme11.1 msec (minimum)
22.2 msec (maximum)
For flaws reallocated after format time using spare
tracks per volume reallocation scheme35 msec (typical)
Overhead time for head switch (512-byte sectors)
in sequential mode0.8 msec
Overhead time for one track cylinder switch
in sequential mode1.2 msec (typical)
Aver age rotational latency5.60 msec
Notes for Sections 4.2.
[1]Execution time is 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, voltage margins and dr ive
orientation. When comparing specified access times, take care to distinguish between typical access
times and maximum access times. Obtain the best comparison by conducting system benchmar k tests
under identical conditions. Maximum times do not include error recovery.
[3]Typical acce ss times are meas ured under nom inal conditions of tempe rature, voltage, and horizontal ori-
entation as measured on a representative sample of drives.
[4]Assumes no errors and no sector reallocations.
[5]Rate measured from the start of the first sector transfer to or from the host.
[6]Assumes system ability to support the 1-byte-wide transfer rate listed and no cable loss.
[7]Assumes system ability to support the 2-byte-wide transfer rate listed and no cable loss.
Elite 47 Product Manual, Rev. A11
4.3S tar t/st op time
Disabling the Motor Start option causes the drive to become ready within 45 seconds after DC power is applied
at nominal voltage. This means the motor starts as soon as power is applied. If a recoverable error condition is
detected during the start sequence, the drive will execute a recovery procedure and may cause the time to
become ready to exceed 45 seconds. During this time the drive responds to some commands over the SCSI
interface. Stop time is less than 40 seconds from removal of DC power.
Enabling the Motor Start option causes the internal controller to accept the commands listed in the
face Product Manual
command, the drive becomes ready for normal operations within 45 seconds (excluding an error recovery procedure). The Motor Start command can also b e used t o comm and t he drive to stop the spindle in less than 40
seconds (see the Start/Stop com man d informat ion in the
There is no power control switch on the drive.
4.4Prefetch/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” operat ions. To sele ct prefetch and cache features the hos t sends the Mo de Select command with the proper values in the applicable bytes in Mode Page 08h (see
Prefetch and cache operation are in dependent features from the standpoin t that eac h is enabled and disabled
independently via the Mode Select command. However, in actual operation the prefetch f eature o verlaps cache
operation somewhat as is noted in Section 4.5.1 and 4.5.2.
All default cache and prefetch Mode parameter values (Mode Page 08h) for standard OEM versions of this
drive family are given in Table 7.
4.5Cache operation
Of the 4,096 Kbytes physical buffer space, approximately 3,442 Kbytes can be used as a cache. The cache
can be divided into logical segments (M ode Select page 08h, byte 13) from which data is read and to wh ich
data is written.
The drive keeps track of the logical block addresses of the data stored in each segment of the cache. If the
cache is enabled (see RCD bit = 0 in Mode page 08h, byte 2, bit 0 in the
requested by the host with a read command is retrieved from the cache, if possible, before any disc access is
initiated. If cache operation is not enabled, the buffer (still segmented with required number of segments) is still
used, but only as circular buffer segments during disc medium read operations (disregarding P refetch operation for 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 retrieved data merely passes through some buffer 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” ratio rule s. See explanations a ssocia ted with Mode
page 02h (disconnect/reconnect control) in the
(77738479) less than 3 secon ds after applying DC power. After receiving the Motor Star t
SCSI Interface Product Manual).
SCSI Interface Product Manual
SCSI Interface Product Manual),
SCSI Interface Product Manual
.
SCSI Inter-
data
).
The following is a simplified description of a read operation with cache operation enabled:
Case A - Read command is received and the first logical block is already in the cache.
1. Drive transfers to the initiator the first logical block requested plus all subsequent contiguous logical blocks
that are already in the cache. This data may be in multiple segments.
2. When a requested logical block is reached that i s not in a ny segment , the drive fetches it and any remaining requested logical block addresses from the disc and puts them in a segm ent of the cache. The dr ive
transfers the remaining requested logical blocks from the cache to the initiator in accordance with the
“buffer-full” ratio specification given in Mode Select Disconnect/Reconnect parameters, page 02h (see the
SCSI Interface Product Manual).
3. The drive prefetches additional logical blocks contiguous to those transferred in step 2 above and stores
them in the segme nt. The drive stops filling the segment when the maximum p refetch value has been
transferred (see the
SCSI Interface Product Manual).
12Elite 47 Product Manual, Rev. A
Case B - Read command is received and the first logical block address requested is not in any segment of the
cache.
1. The drive fetches the reques ted logical blocks from the disc and transfers them into a s egm ent, then from
there to the initiator in accordance with the “buffer-full” ratio specification given in Mode Select Disconnect/
Reconnect parameters, page 02h (see the
2. The drive prefetches additional logical blocks contiguous to those transferred in Case A, step 2 above and
stores th em in the segm ent. The drive s tops filling the segment wh en the maximum prefetch value has
been transferred.
During a prefetch, the drive crosses a cylind er bound ary to fetch data only if the Dis continuity (DISC) bit is s et
to 1 in bit 4 of byte 2 of the Mode Select parameters page 08h. Default is zero for bit 4 (see the
SCSI Interface Product Manual)
.
SCSI Interface
Product Manual).
Each buffer segment is actually a self-contained circular storage (wrap-around occurs), the length of which is
an integer number of disc medium sectors. The wrap-around capability of the individual segments greatly
enhances the buffer’s ov erall performance as a cache storage, allowing a wide range of user selectable configurations, which includes their use in the prefetch operation (if enabled), even when cache operation is disabled
(see Section 4.5.2). The number of segm ents may be selected using the Mode Select com mand, but the size
cannot be directly selected. Size is selected only as a by-product of selecting the segment number specification. The size in Kbytes of each segment is not reported by the Mode Sense command page 08h, bytes 14 and
15. These bytes read 0xFF FF, rega rdless of the num ber of seg ments setting. If a size spec ification is se nt by
the host in a Mode S elect comm and (bytes 14 and 1 5) no n ew segment size is set up by the dr ive, 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 unchangeable parameters (see
integer number of segments from 1 to 16. Divide the 3,442 Kbytes in the buffer by the number of segments to
calculate the segment size. The default is three segments.
SCSI Interface Product Manual).
The dr ive support s operation of any
4.5.1Caching write data
When the WCE (Write Cache Enable) bit is enabled, the drive uses a dr ive buffer storage area where the data
to be written to the drive is stored in one or more segments while the drive performs the Write command. The
write cache uses the same buffer space and segmentation as the read cache. The buffer segmentation
scheme is set up or changed independently, having nothing to do with whether or not read and write caching is
enabled or disabled.
If a 10-byte CDB write command (2 Ah) is iss ued wi th the DPO (Dat a Page Out) bit set to one, no wri te data is
cached but the cache segm ents are still checked and cleared (if nee ded) for any logical blocks that are being
written.
When a write command is issued, the cache is first checked to see if any logical blocks that are to be written
are already stored in the cache from a previous read or write command. If there are, the respective cache segments are cleared. The new data is cached for subsequent read commands.
If the number of write data logical blocks exceeds the size of the segment being written into when the end of
the segment is reached, the data is written into the beginning of the same cache segment, overwriting the data
that was written there at the beginning of the operation. Howev er, the drive does not overwrite data that has not
yet been written to the disc.
Table 7 shows Mode default settings for the drives.
Note.The WC E bit is disabled by default on OEM drives. To enable the WCE bit, change Mode Sense Page
08h, byte 2, bit 2 to a value of 1.
4.5.2Prefetch operation
If the Prefetch feature is enabled, data in contiguous logical blocks on the disc i mmediately beyond that which
was requested by a read command can be retrieved and stored in the buffer for immediate transfer from the
buffer to the host on subsequent read comman ds 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 buffer segment(s), the host can limit the amount of prefetch data to optimize
Elite 47 Product Manual, Rev. A13
system performance. The max prefetch field (bytes 8 and 9) limits the am ount of prefetch. The drive does not
use the prefetch “ceiling” field (byt e s 10 and 11).
During a prefetch operation, the drive crosses a cylinder bo undary to fetch more data only if the Di scontinuity
(DISC) bit is set to one in bit 4 of byte 2 of Mode parameters page 08h.
Whenever prefetch (read look-ahead) is enabled (enabled by DRA = 0), it operates under the control of ARLA
(Adaptive Read Look-Ahead). If the host uses software interleave, A RLA enables prefetch of contiguous blocks
from the disk when it senses t hat a prefetch “hit” w ill l ikely occu r, even if two consecutive read operations were
not for phy sically contiguous bloc ks of data (e .g. “software interleav e”). ARLA disables prefetch when it decides
that a prefetch “hit ” w ill not likely o ccur. If the h ost is not using software int er leave, and if two sequenti al re ad
operations are not for contiguous blocks of data, ARLA disables prefetch, but as long as sequential read operations request contiguous blocks of data, ARLA keeps prefetch enabled.
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