Seagate, Seagate Technology, and the Seagate logo are registered trademarks of Seagate
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Seagate reserves the right to change, without notice, product offerings or specifications. No
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Technology LLC.
Revision status summary sheet
RevisionDateSheets Affected
Rev. A07/15/05All.
Rev. B (Draft 1)03/17/06Pages 25 and 26.
This manual describes Seagate Technology® LLC, Cheetah® 15K.4 FC (Fibre Channel) disc drives.
Cheetah 15K.4 FC drives support the Fibre Channel Arbitrated Loop and SCSI Fibre Channel Protocol specifi-
cations to the extent described in this manual. The Fibre Channel Interface Manual (part number 77767496)
describes the general Fibre Channel Arbitrated Loop characteristics of this and other Seagate Fibre Channel
drives.
Figure 1. Cheetah 15K.4 FC family disc drive
Cheetah 15K.4 FC Product Manual, Rev. B1
2Cheetah 15K.4 FC Product Manual, Rev. B
2.0Applicable standards and reference documentation
The drive has been developed as a system peripheral to the highest standards of design and construction. The
drive depends upon its host equipment to provide adequate power and environment in order to achieve opti
mum performance and compliance with applicable industry and governmental regulations. Special attention
must be given in the areas of safety, power distribution, shielding, audible noise control, and temperature regu
lation. In particular, the drive must be securely mounted in order to guarantee the specified performance char-
acteristics. Mounting by bottom holes must meet the requirements of Section 8.5.
2.1Standards
The Cheetah 15K.4 FC family complies with Seagate standards as noted in the appropriate sections of this
manual and the Seagate Fibre Channel Interface Manual, part number 77767496.
The Cheetah 15K.4 FC disc drive is a UL recognized component per UL1950, CSA certified to CAN/CSA
C22.2 No. 950-95, and VDE certified to VDE 0805 and 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 Communica
tions.
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The design characteristics of the drive serve to minimize radiation when installed in an enclosure that provides
reasonable shielding. As such, the drive is capable of meeting the Class B limits of the FCC Rules and Regula
tions 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 cables should be used, with the shields grounded to the enclosure and to the host con
troller.
2.1.1.1Electromagnetic susceptibility
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 Table
2, DC power requirements.
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Cheetah 15K.4 FC Product Manual, Rev. B3
2.1.2Electromagnetic compliance
Seagate uses an independent laboratory to confirm compliance with the directives/standards for CE Marking
and C-Tick Marking. The drive was tested in a representative system for typical applications. The selected sys
tem 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 with the directives/standards, we cannot guarantee
that all systems will comply. The computer manufacturer or system integrator shall confirm EMC compliance
and provide the appropriate 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 Man
agement Agency (SMA).
Korean MIC
If this model has the Korean Ministry of Information and Communication (MIC) logo, it complies with paragraph
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 the Chinese National Standard (CNS) 13438 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).
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4Cheetah 15K.4 FC Product Manual, Rev. B
2.2Reference documents
Cheetah 15K.4 FC Installation GuideSeagate part number: 100366897
Fibre Channel Interface ManualSeagate part number: 77767496
ANSI Fibre Channel Documents
Project T11/1619-D FC-FS-2 Fibre Channel - Framing and Signaling
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.
8Cheetah 15K.4 FC Product Manual, Rev. B
3.3Performance
• Programmable multi-segmentable cache buffer
• 200 Mbytes/sec maximum instantaneous data transfers per port
• 15k RPM spindle; average latency = 2.0 msec
• Command queuing of up to 128 commands
• Background processing of queue
• Supports start and stop commands (spindle stops spinning)
• Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.)
• Dithering
3.5Formatted capacities
Standard OEM models are formatted to 512 bytes per block. The sector size is selectable at format time. Users
having the necessary equipment may modify the data block size before issuing a format command and obtain
different formatted capacities than those listed.
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 capacity points at certain sector sizes that Seagate guarantees current and future
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 maximum available capacity at a given sector size, but the excess
capacity above the guaranteed level will vary between 10K and 15K families and from generation to gener
ation, 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 for
ward 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 Interface Product 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
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Cheetah 15K.4 FC Product Manual, Rev. B9
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 Cheetah 15K.4 FC Installation Guide (part number 100366897) and
the Safety and Regulatory Agency Specifications, part number 75789512 (unless otherwise specified).
3.7Factory-installed options
You may order the following items which are incorporated at the manufacturing facility during production or
packaged 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. Units shipped individually require additional protection as provided by the single unit
shipping pack. Users planning single unit distribution should specify this option.
•The Cheetah 15K.4 FC Installation Guide, part number 100366897, 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.
3.8User-installed accessories
The following accessories are available. All kits may be installed in the field.
• Evaluation kit, Seagate part number 100364396.
This kit provides an adapter card (“T-card”) to allow cable connections for two FC ports and DC power. You
may purchase this evaluation kit from channel distributors or your Seagate representative.
• Single-unit shipping pack.
10Cheetah 15K.4 FC Product Manual, Rev. B
4.0Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of
Cheetah 15K.4 FC drives.
4.1Internal drive characteristics
ST3146954FCST373554FCST336854FC
Drive capacity146.873.436.7Gbytes (formatted, rounded off value)
Read/write data heads842
Bytes per track471,916471,916471,916Bytes (average, rounded off values)
Bytes per surface18,35118,35118,351Mbytes (unformatted, rounded off value)
Tracks per surface (total)50,86450,86450,864Tracks (user accessible)
Tracks per inch85,00085,00085,000TPI
Peak bits per inch628628628KBPI
Internal data rate685-1,142685-1,142685-1,142Mbits/sec (variable with zone)
Disc rotation speed15k15k15krpm
Avg rotational latency2.02.02.0msec
4.2Seek performance characteristics
See Section 9.5, "FC-AL physical interface" on page 64 and the Fibre Channel Interface Manual (part number
77767496) for additional timing details.
4.2.1Access time
Not including controller overhead
ReadWrite
AverageTypical3.54.0
Single trackTypical0.270.45
Full strokeTypical7.47.9
1.Typical access times are measured under nominal conditions of temperature, voltage,
and horizontal orientation as measured on a representative sample of drives.
2.Access to data = access time + latency time.
1,2
(msec)
Cheetah 15K.4 FC Product Manual, Rev. B11
4.2.2Format command execution time (minutes)
ST3146954FCST373554FCST336854FC
Maximum (with verify)
Maximum (without verify)
906030
453015
4.2.3General performance characteristics
Data buffer to/from disc media (one 512-byte logical block)*
Minimum685 Mbits/sec
Maximum1,142 Mbits/sec
Fibre Channel Interface maximum instantaneous transfer rate200 Mbytes/sec* per port
Logical block sizes
Default is 512-byte data blocks
Variable 512 to 704 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 trackYes
Flaw reallocation performance impact (for flaws reallocated at format time
using the spare sectors per sparing zone reallocation scheme.)
Average rotational latency2.0 msec
*Assumes no errors and no relocated logical blocks. Rate measured from the start of the first logical block transfer to or
from the host.
(dual port = 400 Mbytes/sec*)
Negligible
4.3Start/stop time
If the Motor Start option is disabled, the drive becomes ready within 20 seconds after DC power is applied. If a
recoverable error condition is detected during the start sequence, the drive executes a recovery procedure and
the time to become ready may exceed 20 seconds. Stop time is 30 seconds (maximum) from removal of DC
power.
If the Motor Start option is enabled, the internal controller accepts the commands listed in the Fibre Channel Interface 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 (excluding the error recovery
procedure). The Motor Start command can also be used to command the drive to stop the spindle.
There is no power control switch on the drive.
4.4Prefetch/multi-segmented cache control
The drive provides a prefetch (read look-ahead) and multi-segmented cache control algorithms that in many
cases can enhance system performance. Cache refers to the drive buffer storage space when it is used in
cache operations. To select this feature, the host sends the Mode Select command with the proper values in
12Cheetah 15K.4 FC Product Manual, Rev. B
the applicable bytes in page 08h. Prefetch and cache operations are independent features from the standpoint
that each is enabled and disabled independently using the Mode Select command; however, in actual opera
tion, the prefetch feature overlaps cache operation somewhat as described in sections 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
18.
4.5Cache operation
Note.Refer to the Fibre Channel Interface Manual for more detail concerning the cache bits.
Of the 16,384 kbytes physical buffer space in the drive, approximately 14,218 kbytes can be used as a cache.
Cache segmenting is adjusted dynamically by the disk drive hardware according to the workload being experi
enced by the drive. The drive is capable of dynamically-adjusting up to 256 segments. The number and sizes
of segments are not user-defined.
The drive keeps track of the logical block addresses of the data stored in each segment of the buffer. If the
cache is enabled (see RCD bit in the Fibre Channel Interface Manual
command is retrieved from the buffer, if possible, before any disc access is initiated. If cache operation is not
enabled, the buffer is still used, but only as circular buffer segments during disc medium read operations (dis
regarding 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 the explanation pro
vided with the information about Mode Page 02h (disconnect/reconnect control) in the Fibre Channel Interface
Manual.
), data requested by the host with a read
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The following is a simplified description of the prefetch/cache operation:
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 is not in any cache segment, the drive fetches it and any
remaining requested logical block addresses from the disc and puts them in a segment of the cache. The
drive transfers the remaining requested logical blocks from the cache to the host in accordance with the
Mode Select Disconnect/Reconnect parameters, page 02h.
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, and the first logical block is not in any segment of the cache:
1. The drive fetches the requested logical blocks from the disc and transfers them into a segment, and then
from there to the host in accordance with the Mode Select Disconnect/Reconnect parameters, page 02h.
2. If the prefetch feature is enabled, refer to section 4.5.2 for operation from this point.
During a prefetch, the drive crosses a cylinder boundary to fetch data only if the Discontinuity (DISC) bit is set
to 1 in bit 4 of byte 2 of the Mode Select parameters page 08h. Default is zero for bit 4.
Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical
blocks. The sizes of the segments are determined by the drive’s analysis of the current workload.
Note.The size of each segment is not reported by Mode Sense command page 08h, bytes 14 and 15.
The value 0XFFFF is always reported regardless of the actual size of the segment. Sending a size
specification using the Mode Select command (bytes 14 and 15) does not set up a new segment
size. 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 an unchangeable parameter.
Cheetah 15K.4 FC Product Manual, Rev. B13
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 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 exceed 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; however, the drive does not overwrite data 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 gen
erated.
The Synchronize Cache command may be used to force the drive to write all cached write data to the medium.
Upon completion of a Synchronize Cache command, all data received from previous write commands will have
been written to the medium.
Ta bl e 18 shows the mode default settings for the drive.
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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 are 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 operation hit.
To enable Prefetch, use 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 segments, 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).
When 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
14Cheetah 15K.4 FC Product Manual, Rev. B
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. For additional information about the PM bit, refer to the Unit Attention Parameters page (00h) of the
Mode Sense command (1Ah) in the Fibre Channel Interface Product Manual, part number 77767496.
Cheetah 15K.4 FC Product Manual, Rev. B15
16Cheetah 15K.4 FC Product Manual, Rev. B
5.0Reliability specifications
The following reliability specifications assume correct host and drive operational interface, including all interface timings, power supply voltages, environmental requirements and drive mounting constraints.
1.Error rate specified with automatic retries and data correction with ECC enabled and all flaws reallocated.
1
Less than 10 errors in 108 seeks
Less than 10 errors in 1012 bits transferred (OEM default settings)
Less than 1 sector in 1015 bits transferred
Less than 1 sector in 1021 bits transferred
Less than 1 error in 1012 bits transferred with minimum receive eye.
Less than 1 error in 1014 bits transferred with typical receive eye.
See Section 9.6.4, "FC Differential input." on page 72
5.1Error rates
The error rates stated in this manual assume the following:
• The drive is operated in accordance with this manual using DC power as defined in paragraph 6.2, "DC
power requirements."
• Errors caused by host system failures are excluded from error rate computations.
• Assume random data.
• Default OEM error recovery settings are applied. This includes AWRE, ARRE, full read retries, full write
retries and full retry time.
5.1.1Recoverable Errors
Recovereable errors are those detected and corrected by the drive, and do not require user intervention.
Recoverable Data errors will use correction, although ECC on-the-fly is not considered for purposes of recovered error specifications.
Recovered Data error rate is determined using read bits transferred for recoverable errors occurring during a
read, and using write bits transferred for recoverable errors occurring during a write.
5.1.2Unrecoverable Errors
Unrecoverable Data Errors (Sense Key = 03h) are specified at less than 1 sector in error per 1015 bits transferred. Unrecoverable Data Errors resulting from the same cause are treated as 1 error for that block.
Cheetah 15K.4 FC Product Manual, Rev. B17
5.1.3Seek errors
A seek error is defined as a failure of the drive to position the heads to the addressed track. After detecting an
initial seek error, the drive automatically performs an error recovery process. If the error recovery process fails,
a seek positioning error (Error code = 15h or 02h) will be reported with a Hardware error (04h) in the Sense
Key. Recoverable seek errors are specified at Less than 10 errors in 10
8
seeks. Unrecoverable seek errors
(Sense Key = 04h) are classified as drive failures.
5.1.4Interface errors
An interface error is defined as a failure of the receiver on a port to recover the data as transmitted by the
device port connected to the receiver. The error may be detected as a running disparity error, illegal code, loss
of word sync, or CRC error. The total error rate for a loop of devices is the sum of the individual device error
rates.
5.2Reliability and service
You can enhance the reliability of Cheetah K15.4 disc drives by ensuring that the drive receives adequate cooling. Section 6.0 provides temperature measurements and other information that may be used to enhance the
service life of the drive. Section 8.3 provides recommended air-flow information.
5.2.1Mean time between failure (MTBF)
The production disc drive achieves an MTBF of 1,400,000 hours when operated in an environment that
ensures the case temperatures specified in Section
specification limits of the operating environment will not affect MTBF performance. Operating the drive at case
temperatures above these values will adversely affect the drive’s ability to meet specifications (see
"Environmental limits").
6.4.1 are not exceeded. Short-term excursions up to the
Section 6.4,
The MTBF target is specified as device power-on hours (POH) for all drives in service per failure.
The following expression defines MTBF:
MTBF per measurement period = Estimated power-on operating hours in the period
Number of drive failures in the period
Estimated power-on operating hours means power-on hours per disc drive times the total number of disc
drives in service. Each disc drive must have accumulated at least nine months of operation. Data is 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
• Operating at nominal voltages
• System provides adequate cooling to ensure the case temperatures specified in Section 6.4.1 are not
exceeded.
Drive failure means any stoppage or failure to meet defined specifications caused by drive malfunction.
A S.M.A.R.T. predictive failure indicates that the drive is deteriorating to an imminent failure and is considered
an MTBF hit.
5.2.2Preventive maintenance
No routine scheduled preventive maintenance is required.
18Cheetah 15K.4 FC Product Manual, Rev. B
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