in the United States and/or other countries. Savvio, SeaTools and SeaTDD are either trademarks or registered trademarks of Seagate Technology LLC or one of its affiliated companies in the United States and/or
other countries. All other trademarks or registered trademarks are the property of their respective owners.
One gigabyte, or GB, equals one billion bytes when referring to hard drive capacity. Accessible capacity
may vary depending on operating environment and formatting. Quantitative usage examples for various
applications are for illustrative purposes. Actual quantities will vary based on various factors, including file
size, file format, features and application software. Seagate reserves the right to change, without notice,
product offerings or specifications.
This manual describes Seagate® SavvioTM disc drives.
Savvio SCSI drives support the small computer system interface (SCSI) as described in the ANSI SCSI SPI-3
interface specifications to the extent described in this manual. The SCSI Interface Product Manual (part num-
ber 75789509) describes gene ral SCSI inte rface characteristics of this an d othe r families of Seagate dr ives.
Figure 1. Savvio SCSI family drive
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Savvio SCSI Product Manual, Rev. D
3
2.0Applicable standards and reference documentation
The drive has been d evelope d as a system p eriphe ral to the hig hest st and ards of desig n and constru c tion. The
drive depends upon its host equipment to provide adequate power and environment in order to achieve optimum performance and compliance with applicable industry and governmental regulations. Special attention
must be given in the areas of safety, power distribution, shielding, au di ble noise con trol , an d tempe ratu re reg ulation. In particular, the drive must be securely mounted in order to guarantee the specified performance characteristics. Mounting by bottom holes must meet the requirements of Section 8.3.
2.1Standards
The Savvio SCSI family complies with Seagate standards as noted in the appropriate sections of this Manual
and the Seagate SCSI Interface Product Manual, part number 75789509.
The Savvio SCSI disc drive is a UL recognized component per UL1950, CSA certified to CSA C22.2 No. 95095, and VDE or TUV certified to EN60950.
2.1.1Electromagnetic compatibility
The drive, as delivered, is designed for system integration and installation into a suitable enclosure prior to
use. As such the drive is supplied as a subassembly and is not subject to Subpart B of Part 15 of the FCC
Rules and Regulations nor the Radio Interference Regulations of the Canadian Department of Communications.
The design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides
reasonable shield ing. As such, t he dr ive is cap able of me eting th e C lass B l imit s of the FC C Rules a nd R eg ulations of the Canadian Department of Communications when properly packaged. However, it is the user’s
responsibility to assure that the drive meets the appropriate EMI requirements in their system. Shielded I/O
cables may be required if the enclosure does not provide adequate shielding. If the I/O cables are external to
the enclosure, shielded cabl es sh ould be u sed, wi th the shields gr ounde d to the enclosur e and to the host co ntroller.
2.1.2Electromagn etic susc ept ibili ty
As a component assembly, the drive is not required to meet any susceptibility performance requirements. It is
the responsibility of those integrating the drive within their systems to perform those tests required and design
their system to ensure that equipment operating in the same system as the drive or external to the system
does not adversely affect the performance of the drive. See Section 5.1.1 and Table 2, DC power requirements.
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Savvio SCSI Product Manual, Rev. D
2.2Electromagn etic complia nce
Seagate uses an independent laboratory to confirm compliance to the directives/standard(s) for CE Marking
and C-Tick Marking. T he dr ive was tested in a r epre sent ative system for typica l applications. The select ed system represents the most popular characteristics for test platforms. The system configurations include:
• Typical current use microprocessor
• 3.5-inch floppy disc drive
• Keyboard
• Monitor/display
• Printer
• External modem
• Mouse
Although the test system with this Seagate model complies to the directives/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 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.
Australian C-Tick
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).
Korean MIC
If this model has the Korean Min ist ry of Infor mat ion and Com munication (MIC) logo, it complie s with par agr aph
1 of Article 11 of the Electromagnetic Compatibility (EMC) Control Regulation and meets the Electromagnetic
Compatibility Framework requirements of the Radio Research Laboratory (RRL) Ministry of Information and
Communication Republic of Korea.
Taiwanese BSMI
If this model has two Chinese words meaning “EMC certification” followed by an eight digit identification number, as a Marking, it complies with Chinese National Standard (CNS) 13438 and meets the Electromagnetic
Compatibility (EMC) Framework requirements of the Taiwanese Bureau of Standards, Metrology, and Inspection (BSMI).
SFF-8451Specification for SCA-2 Unshielded Connections
Package Test SpecificationSeagate P/N 30190-001 (under 100 lb.)
Package Test SpecificationSeagate P/N 30191-001 (over 100 lb.)
Specification, Acoustic Test Requirements, and ProceduresSeagate P/N 30553-001
In case of conflict between this document and any referenced document, this document takes precedence.
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Savvio SCSI Product Manual, Rev. D
7
3.0General description
Savvio SCSI drives combine Tunneling Magnetoresistive (TMR) heads and a wide Ultra320 SCSI interface to
provide high performance, high capacity data storage for a variety of systems including engineering workstations, network servers, mainframes, and supercomputers.
Ultra320 SCSI uses negotiated tra nsfer rates. T hese transfer rates will occur only if your host adap ter sup port s
these data tran sfer r ates and is co mp atible with the requ ired h ardwa re r equir emen ts of the I/O circu it type. This
drive also operates at SCSI-1 and SCSI-2 data transfer rates for backward compatibility with non-Ultra/Ultra2/
Ultra320 SCSI host adapters.
Table 1 lists the features that differentiate the Savvio SCSI models.
T ab le 1:Drive model number vs. differentiating features
Model numberNumber of headsFormatted Capacity
ST973401LC
ST936701LC
4
2
73.4 Gbytes
36.7 Gbytes
[1]See Section 9.6 for details and definitions.
The drive records and recovers data on approximately 2.5-inch (65 mm) non-removable discs.
The drive supports the Small Computer System Interface (SCSI) as described in the ANSI SCSI interface
specifications to the extent described in this manual, which defines the product performance characteristics of
the Savvio SCSI family of drives, and the SCSI Interface Product Manual, part number 75789509, 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 r el ieve the h ost fr om t he ne cessity of know ing the physi cal ch aracte ristics 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.
Never disassemble the HDA and do not attempt to service items in the sealed enclosure (heads, media, actuator, etc.) as this requires special facilities. The drive contains no replaceable parts. Opening the HDA voids
your warranty.
Savvio SCSI drives u s e a dedica ted la ndi ng zone at t he inn erm ost r adi us of th e m edia t o eli m inate the p ossibil ity 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 automatically disengages when power is applied to the drive and
the head load process begins.
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Savvio SCSI Product Manual, Rev. D
Savvio SCSI drives decode track 0 location data from the servo data embedded on each surface to eliminate
mechanical transducer adjustments and related reliability concerns.
A high-performance actuator assembly with a low-inertia, balanced, patented, straight-arm design provides
excellent performance with minimal power dissipation.
3.1Standard features
The Savvio SCSI family has the following standard features:
• Integrated Ultra320 SCSI controller
• Multimode SCSI drivers and receivers—single-ended (SE) and low voltage differential (LVD)
• 16 bit I/O data bus
• Asynchronous and synchronous data transfer protocol
• Firmware downloadable via SCSI interface
• Selectable even byte sector sizes from 512 to 528 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)
• ECC maximum burst correction length of 320 bits
• No preventative maintenance or adjustment required
• Dedicated head landing zone
• Embedded servo design
• Self diagnostics performed when power is applied to the drive
The media used on the drive has an aluminum substrate coated with a thin film magnetic material, overcoated
with a proprietary protective layer for improved durability and environmental protection.
3.3Performance
• Supports industry standard Ultra320 SCSI interface
• Programmable multi-segmentable cache buffer (see Section 4.5)
• 10,000 RPM spindle. Average latency = 3.00 ms
• Command queuing of up to 64 commands
• Background processing of queue
• Supports start and stop commands (spindle stops spinning)
Savvio SCSI Product Manual, Rev. D
9
3.4Reliability
• Mean time Between Failure (MTBF) of 1,400,000 hours
• LSI circuitry
• Balanced low mass rotary voice coil actuator
• Incorporates industry-standard Self-Monitoring, Analysis and Reporting Technology (S.M.A.R.T.)
• 5-year warranty
3.5Fo rm a tte d ca pacities
St an dard OEM mo del s ar e formatte d to 512 bytes per block. The sector size is sel ect ab le at fo rma t 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.
To provide a stable target capacity environment and at the same time provide users with flexibility if they
choose, Seagate recommends product planning in one of two modes:
1. Seagate designs specify cap acity po i nt s at cert ain sect or si zes tha t Seagate gu ara ntees cur ren t and futu re
products will meet. We recommend customers use this capacity in their project planning, as it ensures a
stable operating point with backward and forward compatibility from generation to generation. The current
guaranteed operating points for this product are:
2. Seagate drives also may be used at the maxi mu m available cap acity at a given secto r size, but the excess
capacity above the guaranteed level will vary between other drive families and from generation to generation, depending on how each sector size actually formats out for zone frequencies and splits over servo
bursts. This added capacity potential may range from 0.1 to 1.3 percent above the guaranteed capacities
listed above. Using the drives in this manner gives the absolute maximum capacity potential, but the user
must determine if the extra capacity potential is useful, or whether their assurance of backward and forward compatibility takes precedence.
3.5.1Programmable drive capacity
Using the Mode Select command, the drive can change its capacity to something less than maximum. See the
Mode Select Parameter List table in the SCSI Command Reference Manual. Refer to the Parameter list block
descriptor number of blocks field. A value of zero in the number of blocks field indicates that the drive shall 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 of LBAs changes the total drive capacity to the value in the block descriptor number of
blocks field. A value greater than the maximum number of LBAs is rounded down to the maximum capacity.
3.6Factory installed accessories
OEM Standard drives are shipped with the Savvio SCSI Installation Guide, part number 100293076, and the
Safety and Regulatory Agency Specifications, part number 75789512 (unless otherwise specified).
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Savvio SCSI Product Manual, Rev. D
3.7Options (factory installed)
All customer requested options are incorporated during production or packaged at the manufacturing facility
before shipping. Some of the options available are (not an exhaustive list of possible options):
• Other capacities can be ordered depending on sparing scheme and sector size requested.
• Single unit shipping pack. The drive is normally shipped in bulk packaging to provide maximum protection
against transit damage. U nit s shipped individually require add itional pro tection as pr ovided by th e singl e unit
shipping pack. Users planning single unit distribution should specify this option.
• The Savvio SCSI Installation Guide , part number 100293076, is usually included with each standard OEM
drive shipped, but extra copies may be ordered.
• The Safety and Regulatory Agency Specifications, part number 75789512, is usually included with each
standard OEM drive shipped, but extra copies may be ordered.
3.8Accessories (user installed)
The following accessories are available. All accessories may be installed in the field.
• Single unit shipping pack.
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11
4.0Performance characteristic
4.1Intern al drive char acterist ics (transparent to user)
ST973401ST936701
Drive capacity73.436.7GBytes (formatted, rounded off values)
Read/write heads42
Bytes/track360,000360,000Kbytes (average, rounded off values)
Bytes/surface18,38718,387Mbytes (formatted, rounded off values)
Tracks/surface (total)51,05251,052Tracks (user accessible)
Tracks/inch105105KTPI
Peak bits/inch660660KBPI
Internal data rate506-753506-753Mbits/sec (variable with zone)
Disc rotational speed10,00910,009revolutions/min (RPM)
Average rotational latency3.003.00msec
4.2SCSI performance characteristics (visible to user)
The values given in Section 4.2.1 apply to all models of the Savvio SCSI family unless otherwise specified.
Refer to Section 9.9 and to the SCSI Interface Product Manual for additional timing details.
4.2.1Access time [5]
Including controller overhead
(without disconnect) [1] [3]
Drive levelDrive level
Not including controller overhead
(without disconnect) [1] [3]
ReadWriteReadWrite
msec msec
Average—Typical [2]4.705.104.504.90
Single Track—Typical [2]0.650.950.450.75
Full Stroke—Typical [2]8.709.108.508.90
4.2.2Format command execution time (minutes) [1]
ST973401ST936701
Maximum (with verify)5226
Maximum (no verify)2613
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Savvio SCSI Product Manual, Rev. D
4.2.3Generalized performance characteristics
Minimum sector interleave1 to 1
Data buffer transfer rate to/from disc media (one 512-byte sector):
Minimum [3]*63Mbytes/sec
Maximum [3]94Mbytes/sec
SCSI interface data transfer rate (asynchronous):
Maximum instantaneous one byte wide5.0 Mbytes/sec [4]
Maximum instantaneous two bytes wide10.0 Mbytes/sec [4]
Synchronous transfer rate Ultra320 SCSI
In low voltage differential (LVD) interface mode5.0 to 320 Mbytes/sec
Sector Sizes:
Default512 byte user data blocks
Variable512 to 528 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.
Read/write consecutive sectors on a track Yes
Flaw reallocation performance impact (for flaws reallocated at format time using
the spare sectors per sparing zone reallocation scheme.)
Average rotational latency3.00 msec
Notes for Section 4.2.
[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]Typical access times are measured under nominal conditions of temperature, voltage, and horizontal ori-
entation as measured on a representative sampl e of drives.
[3]Assumes no errors and no sector has been relocated.
[4]Assumes system ability to support the rates listed and no cable loss.
[5]Access time = controller overhead + average seek time and applies to all data transfer commands.
Access to data = access time + latency time.
4.3Start/stop time
After DC power at nominal voltage has been applied, the drive becomes ready within 20 seconds if the Motor
Start Option is disabled (i.e. the motor starts as soon as the power has been applied). If a recoverable error
condition is detected during the start sequence, the drive executes a recovery procedure which may cause the
time to become ready to exceed 20 seconds. During spin up to ready time the drive responds to some commands over the SCSI interface in less than 3 seconds after application of power. Stop time is 30 seconds from
removal of DC power.
If the Motor S ta rt Option is ena bled, the intern al controller accepts the comm ands li sted in the SCSI Comm and
Reference 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 20 seconds typically (excluding an error
recovery procedure). The Motor Start Command can also be used to command the drive to stop the spindle
(see the SCSI Command Reference Manual).
Negligible
There is no power control switch on the drive.
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13
4.4Pr efetch/multi-s egmented cache co ntrol
The drive provides prefetch (read look-ahead) and multi-segmented cache control algorithms that in many
cases can enhance syste m pe rfor mance . “Ca che” as used herein refer s to th e dr ive bu f fer st orag e space when
it is used in cache oper ations. To select prefetch a nd cache features the host sends the Mode Select comm and
with the proper values in the applicabl e byte s in Mode Pa ge 08h (see the SCSI Co mman d Refere nce Manu al ).
Prefetch and cache operation are independent features from the standpoint that each is enabled and disabled
independently via the Mode Select command. However, in actual operation the prefetch feature overlaps
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 Tables 15.
4.5Cache operation
In general, 7,100 kbytes of the physi cal buf fe r sp ace in the dri ve can be used as stor age sp ace for cache operations. The buffer can be divided into logical segments (Mode Select Page 08h, byte 13) from which data is
read and to which data is written. The drive supports a maximum of 64 cache segments. The drive maintains a
table of logical block disc 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 Command Reference 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 buffer (still segmented with required number of segments) is
still used, but only as circular buffer segments during disc medium read operations (disregarding Prefetch
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 rules. See explanations associated with Mode
page 02h (disconnect/reconnect control) in the SCSI Command Reference Manual.
The following is a simplified description of a read operation with cache operation enabled:
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 LBs that are already in
the cache. This data may be in multiple segments.
2. When the requested LB is r eached that i s n ot in an y cache se gmen t, the dri ve fe tches it a nd an y rem aini ng
requested LBs from the disc and puts them in a segment of the cache. The drive transfers the remaining
requested LBs from the cache to the host in accordance with the disconnect/reconnect specification mentioned above.
3. If the prefetch feature is enabled, refer to Section 4.5.2 for operation from this point.
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 LBs from the disc and transfers 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 enabled, refer to Section 4.5.2 for operation from this point.
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 buf fer’s overa ll performance as a cache stora ge, al lowi n g a wide range of user select able con fi gurations, which includes the ir use i n the prefetch operation (if enabled) , even whe n cache op erati o n is disa bled
(see Section 4.5.2). The number of segments is set dynamically by the drive and cannot be set by the host.
The size in Kbytes of each segment is not reported by the Mode Sense command page 08h, bytes 14 and 15.
The value 0XFFFF is always reported. 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 unchangeable parameters (see
SCSI Command Reference Manual).
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Savvio SCSI Product Manual, Rev. D
4.5.1Caching write data
Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to
be written to the medium is stored in one or more segments while the drive performs the write command.
If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made available for future read cache hits. The same buffer space and segmentation is used as set up for read functions.
The buffer segmentation scheme is set up or changed independently, having nothing to do with the state of
RCD. When a write command is issued, if RCD=0, 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 dat a is writt en into the beginning of the same cache segment, overwriting the dat a
that was written the re at th e b eginning of the operation. However, the drive does not ove rwri te dat a that has not
yet been written to the medium.
If write caching is enabled (WCE=1), then the drive may return GOOD status on a write command after the
data has been transferred into the cache, but before the data has been written to the medium. If an error
occurs while writing the data to the medium, and GOOD status has already been returned, a deferred error will
be generated.
The Synchronize Ca che command may be used to force the drive to write all cached wri te dat a to the med ium.
Upon completion of a Synchronize Cache command, all data received from previous write commands will have
been written to the medium.
Tables 15 show Mode default settings for the drives.
4.5.2Prefetch operation
If the Prefetch feature is enabled, data in contiguous logical blocks on the disc immediately 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 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 operat ion hit. P refe tch is enab le d using M ode Sel ect p age 08h, byt e 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 system performance. The max prefetch field (bytes 8 and 9) limits the amount of prefetch. The drive does not use the
Prefetch Ceiling field (bytes 10 and 11).
During a prefetch operation, the drive crosses a cylinder boundary to fetch more data only if the Discontinuity
(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, ARLA enables prefetch of contiguous
blocks from the disc when it senses that a prefetch hit will likely occur, even if two consecutive read operations
were not for physically contiguous blocks of data (e.g., “software interleave”). 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 keeps prefetch enabled.
4.5.3Optimizing cache performance for desktop and server applications
Desktop and server applications require different drive caching operations for optimal performance. This
means it is difficult to provide a single configuration that meets both of these needs. In a desktop environment,
you want to configure the cache to respond quickly to repetitive accesses of multiple small segments of data
without taking the time to “look ahead” to the next contiguous segments of data. In a server environment, you
Savvio SCSI Product Manual, Rev. D
15
want to configure the cache to provide large volumes of sequential data in a non-repetitive manner. In this
case, the ability of the cache to “look ahead” to the next contiguous segments of sequential data is a good
thing.
The Performance Mode (PM) bit controls the way the drive switches the cache buffer into different modes of
segmentation. In “server mode” (PM bit = 0), the drive can dynamically change the number of cache buffer
segments as needed to optimize the performance, based on the command stream from the host. In “desktop
mode” (PM bit = 1), the number of segments is maintained at the value defined in Mode Page 8, Byte 13, at all
times (unless changed by using a Mod e Select comman d). Fo r addi tion al information about the PM bit, refer to
the Unit Attention Parameters page (00h) of the Mode Sense command (1Ah) in the SCSI Interface Product Manual, part number 75789509.
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17
5.0Reliability specifications
The following reliability specifications assume correct host/drive operational interface, including all interface
timings, power supply voltages, environmental requirements and drive mounting constraints (see Section 8.3).
Seek Errors
Read Error Rates [1]
Recovered DataLess than 10 errors in 10
Unrecovered DataLess than 1 sector in 1015 bits transferred (OEM default settings)
Miscorrected DataLess than 1 sector in 1021 bits transferred
MTBF1,400,000 hours
Service Life5 years
Preventive MaintenanceNone required
Note.
[1]Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.
5.1Error rates
The error rates stated in this specification assume the following:
• The drive is operated per this specification using DC power as defined in this manual (see Section 6.2).
• The drive has been formatted with the SCSI FORMAT command.
• Errors caused by media defects or host system failures are excluded from error rate computations. Refer to
Section 3.2, “Media Characteristics.”
• Assume random data.
Less than 10 in 108 seeks
12
bits transferred (OEM default settings)
5.1.1Environmental interference
When evaluating systems operation under conditions of Electromagnetic Interference (EMI), the performance
of the drive within the system shall be considered acceptable if the drive does not generate an unrecoverable
condition.
An unrecoverable error, or unrecoverable condition, is defined as one that:
• Is not detected and corrected by the drive itself;
• Is not capabl e o f be ing de tected from the err or or faul t st at us pr ovi ded thro ugh the d rive o r S CSI inter face; or
• Is not capable of being recovered by normal drive or system recovery procedures without operator interven-
tion.
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Savvio SCSI Product Manual, Rev. D
5.1.2Read errors
Before determination or measurement of read error rates:
• The data tha t is to be u sed fo r m easur eme nt of read er ror rate s must be verified as being w rit ten co rrect ly on
the media.
• All media defect induced errors must be excluded from error rate calculations.
5.1.3Write errors
Write errors can occur as a result of media defects, environmental interference, or equipment malfunction.
Therefore, write errors are not predictable as a function of the number of bits passed.
If an unrecoverable write error occurs because of an equipment malfunction in the drive, the error is classified
as a failure affecting MTBF. Unrecoverable write errors are those which cannot be corrected within two
attempts at writing the record with a read verify after each attempt (excluding media defects).
5.1.4Seek errors
A seek error is defined as a failure of the drive to position the heads to the addressed track. There shall be no
more than ten recoverable seek errors in 108 physical seek operations. After detecting an initial seek error, the
drive automatically performs an error recovery process. If the error recovery process fails, a seek positioning
error (15h) is reported with a Hardware error (4h) reported in the Sense Key. This is an unrecoverable seek
error. Unrecoverable seek errors are classified as failures for MTBF calculations. Refer to the SCSI Interface Product Manual, part number 75789509, for Request Sense information.
5.2Reliability and service
You can enhance the reliability of Savvio SCSI disc drives by ensuring that the drive receives adequate cooling. Section 6 provides temperature measurements and other information that may be used to enhance the
service life of the drive. Section 8.2 provides recommended air-flow information.
5.2.1Mean time between failure
The production disc drive shall achieve an MTBF of 1,400,000 hours when operated in an environment that
ensures the HDA case temperatures specified in Section 6.4 are not exceeded. Short-term excursions up to
the specification limits of the operating environment will not affect MTBF performance. Continual or sustained
operation at case temperatures above the values shown in Section 6.4.1 may degrade product reliability.
The MTBF target is specified as device power-on hours (POH) for all drives in service per failure.
Estimated power-on operating hours in the period = MTBF per measurement period
Number of drive failures in the period
Estimated power-on operation hours means power-up hours per disc drive times the total number of disc
drives in service. Each disc drive shall have accumulated at least nine months of operation. Data shall be calculated on a rolling average base for a minimum period of six months.
MTBF is based on the following assumptions:
• 8,760 power-on hours per year.
• 250 average on/off cycles per year.
• Operations at nominal voltages.
• Systems will provide adequate cooling to ensure the case temperatures specified in Section 6.4.1 are not
exceeded.
Drive failure means any stoppage or substandard performance caused by drive malfunction.
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