Seagate, Seagate Technology, and the Seagate logo are registered trademarks of Seagate Technology LLC.
Cheetah, SeaFAX, SeaFONE, SeaBOARD, and SeaTDD are either registered trademarks or trademarks of
Seagate Technology LLC. Other product names are registered trademarks or trademarks of their owners.
Seagate reserves the right to change, without notice, product offerings or specifications. No part of this publica-
tion may be reproduced in any form without written permission of Seagate Technology LLC.
Product Manual 100195490 is Volume 1 of a two volume document with the Fibre Channel Interface
information in the Fibre Channel Interface Manual, part number 77767496.
If you need the Fibre Channel Interface information, order the Fibre Channel Interface Manual, part
number 77767496.
This manual describes Seagate Technology® LLC, Cheetah® 10K.6 FC (Fibre Channel) disc drives.
Cheetah 10K.6 FC drives support the Fibre Channel Arbitrated Loop and SCSI Fibre Channel Protocol specifications to the extent described in this manual. The
describes the general Fibre Channel Arbitrated Loop characteristics of this and other Seagate Fibre Channel
drives.
Figure 1.Cheetah 10K.6 FC family disc drive
Fibre Channel Interface Manual
(part number 77767496)
2Cheetah 10K.6 FC Product Manual, Rev. B
Cheetah 10K.6 FC Product Manual, Rev. B3
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 optimum 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 regulation. 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 8.5.
2.1Standards
The Cheetah 10K.6 FC family complies with Seagate standards as noted in the appropriate sections of this
manual and the Seagate
The Cheetah 10K.6 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 Communications.
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 Regulations 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 controller.
Fibre Channel Interface Manual
, part number 77767496.
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 Section 5.1.1 and Table 1, DC power requirements.
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 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 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.
4Cheetah 10K.6 FC Product Manual, Rev. B
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 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 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).
2.2Reference documents
Cheetah 10K.6 FC Installation Guide
Seagate part number: 100195492
Fibre Channel Interface Manual
Seagate part number: 77767496
ANSI Fibre Channel Documents
X3.230-1994FC Physical and Signaling Interface (FC-PH)
X3.297.1997FC-PH-2 Fibre Channel Physical and Signaling Interface-2
X3.303.1998FC-PH-3 Fibre Channel Physical and Signaling Interface-3
X3.272-1996FC Arbitrated Loop (FC-AL)
X3.269-1996Fibre Channel Protocol for SCSI (FCP)
NCITS TR-19Private Loop SCSI Direct Attach (PLDA)
NCITS TR-20Fabric Loop Attachment (FC-FLA)
SFF-8045 Specification for 40-pin SCA-2 Connector with Parallel Selection
SFF-8067 Specification for 40-pin SCA-2 Connector with Bidirectional Enclosure Services
Interface
ANSI Small Computer System Interface (SCSI) Documents
X3.131-1994(SCSI-2)
X3.270-1996(SCSI-3) Architecture Model
NCITS 305-199X(SCSI-3) Enclosure Services
Specification for Acoustic Test Requirement and Procedures
Seagate part number: 30553-001
Package Test SpecificationSeagate P/N 30190-001 (under 100 lb.)
Package Test SpecificationSeagate P/N 30191-001 (over 100 lb.)
In case of conflict between this document and any referenced document, this document takes precedence.
Cheetah 10K.6 FC Product Manual, Rev. B5
3.0General description
Cheetah 10K.6 FC drives combine giant magnetoresistive (GMR) heads, partial response/maximum likelihood
(PRML) read channel electronics, embedded servo technology, and a Fibre Channel interface to provide high
performance, high capacity data storage for a variety of systems including engineering workstations, network
servers, mainframes, and supercomputers.
Cheetah 10K.6 FC drives are random access storage devices designed to support the Fibre Channel Arbitrated Loop (FC-AL) and SCSI Fibre Channel Protocol as described in the ANSI specifications, this document,
and the
acteristics of this drive. Cheetah 10K.6 FC drives are classified as intelligent peripherals and provide level 2
conformance (highest level) with the ANSI SCSI standard.
See Figure 2 for an exploded view of the drive. Never disassemble the HDA. This exploded view is for information only. Do not attempt to service items in the sealed enclosure (heads, media, actuator, etc.) as this requires
special facilities. The drive contains no parts replaceable by the user and opening the HDA for any reason
voids your warranty.
Fibre Channel Interface Manual
(part number 77767496) which describes the general interface char-
Figure 2.Cheetah 10K.6 FC disc drive
Cheetah 10K.6 FC drives use a dedicated landing zone at the innermost radius of the media to eliminate the
possibility of destroying or degrading data by landing in the data zone. The heads automatically go to the landing zone when power is removed from the drive.
An automatic shipping lock prevents potential damage to the heads and discs that results from movement during shipping and handling. The shipping lock disengages and the head load process begins when power is
applied to the drive.
Cheetah 10K.6 FC drives decode track 0 location data from the servo data embedded on each surface to eliminate mechanical transducer adjustments and related reliability concerns.
The drives also use a high-performance actuator assembly with a low-inertia, balanced, patented, straight arm
design that provides excellent performance with minimal power dissipation.
6Cheetah 10K.6 FC Product Manual, Rev. B
3.1Standard features
Cheetah 10K.6 FC drives have the following standard features:
• Integrated dual port FC-AL controller
• Concurrent dual port transfers
• Support for FC arbitrated loop, private and public attachment
• Differential copper FC drivers and receivers
• Downloadable firmware using the FC-AL interface
• Supports SCSI enclosure services via interface connector
• 128-deep task set (queue)
• Supports up to 32 initiators
• Drive selection ID and configuration options are set on the FC-AL backpanel or through interface commands. Jumpers are not used on the drive.
• Fibre Channel worldwide name uniquely identifies the drive and each port
• User-selectable logical block size (512 to 528 bytes per logical block) in even numbers of blocks
• Selectable frame sizes from 256 to 2,112 bytes
• Industry standard 3.5-inch low profile form factor dimensions
• Programmable logical block reallocation scheme
• Flawed logical block reallocation at format time
• Programmable auto write and read reallocation
• Reed-Solomon error correction code
• Sealed head and disc assembly (HDA)
• No preventive maintenance or adjustments required
• Dedicated head landing zone
• Automatic shipping lock
• Embedded Grey Code track address and servo wedge address to eliminate seek errors
• Self-diagnostics performed at power on
• 1:1 interleave
• Zone bit recording (ZBR)
• Vertical, horizontal, or top down mounting
• Dynamic spindle brake
• 8,192 Kbyte data buffer. See Section 4.5.
• Embedded servo design
• Reallocation of defects on command (Post Format)
The media used on the drive has a diameter of approximately 84 mm (approximately 3.3 inches). The aluminum substrate is coated with a thin film magnetic material, overcoated with a proprietary protective layer for
improved durability and environmental protection.
3.3Performance
• Programmable multi-segmentable cache buffer
• 200 Mbytes/sec maximum instantaneous data transfers per port
• Self-Monitoring Analysis and Reporting Technology (S.M.A.R.T.)
• Dithering
3.5Unformatted and formatted capacities
Formatted capacity depends on the spare reallocation sectors scheme selected, the number of data tracks per
sparing zone, and the number of alternate sectors (LBAs) per sparing zone. The following table shows the
standard OEM model capacity:
Standard OEM models are formatted to 512 bytes per block. You can order other capacities by requesting a different sparing scheme and logical block size.
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. Cheetah
10K.6 FC drives use a zone sparing scheme. The drive is divided into frequency zones with a variable number
of spares in each zone.
Note.For 2 gigabit operation, sector sizes must be divisible by 8.
3.6Programmable drive capacity
Using the Mode Select command, the drive can change its capacity to something less than maximum. See the
Mode Select (6) parameter list table in the
Fibre Channel Interface Manual
, part number 7767496. A value of
zero in the Number of Blocks field indicates that the drive will not change the capacity it is currently formatted
to have. A number other than zero and less than the maximum number of LBAs in the Number of Blocks field
changes the total drive capacity to the value in the Number of Blocks field. A value greater than the maximum
number of LBAs is rounded down to the maximum capacity.
3.7Factory-installed accessories
OEM standard drives are shipped with the
Cheetah 10K.6 FC Installation Guide
(part number 100195492).
3.8Factory-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 10K.6 FC Installation Guide,
part number 100195492, 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.
3.9User-installed accessories
The following accessories are available. All kits may be installed in the field.
• Evaluation kit, part number 73473641.
This kit provides an adapter card (“T-card”) to allow cable connections for two FC ports and DC power.
• Single-unit shipping pack.
8Cheetah 10K.6 FC Product Manual, Rev. B
Cheetah 10K.6 FC Product Manual, Rev. B9
4.0Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of
Cheetah 10K.6 FC drives.
1.Execution time measured from receipt of the FCP Command to the FCP Response.
2.Assumes no errors and no sector has been relocated.
3.Typical access times are measured under nominal conditions of temperature, voltage, and hor-
izontal orientation as measured on a representative sample of drives.
4.Access time = controller overhead + average seek time.
Access to data = controller overhead + average seek time + latency time.
3,4
3,4
3,4
4.905.504.705.30
0.550.750.350.55
9.209.709.009.50
1, 2
(msec)
Not including controller
overhead
1,2
(msec)
4.2.2Format command execution time (in minutes)
ST3146807FCST373307FCST336607FC
Maximum (with verify)
Maximum (without verify)
1809045
904530
10Cheetah 10K.6 FC Product Manual, Rev. B
4.2.3General performance characteristics
Minimum sector interleave1 to 1
Data buffer to/from disc media (one 512-byte logical block)*
Minimum59 MBytes/sec
Average94 MBytes/sec
Maximum
105 MBytes/sec
Fibre Channel Interface maximum instantaneous transfer rate1 GHz
106 Mbytes/sec* per
port (dual port = 212
Mbytes/sec*)
Logical block sizes
Default is 512-byte data blocks
Variable 512 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 trackYes
Flaw reallocation performance impact (for flaws reallocated at format time
using the spare sectors per sparing zone reallocation scheme.)
Overhead time for head switch in sequential mode
Overhead time for one track cylinder switch in sequential mode
Average rotational latency
*Assumes no errors and no relocated logical blocks. Rate measured from the start of the first logical block transfer to or
from the host.
Negligible
0.8 msec
1.2 msec (typical)
2.99 msec
2 GHz
212 Mbytes/sec* per
port (dual port = 424
Mbytes/sec*)
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 30 seconds. Stop time is less than 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
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 operation, 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 15.
4.5Cache operation
Note.Refer to the
Fibre Channel Interface Manual
for more detail concerning the cache bits.
Of the 8,192 kbytes physical buffer space in the drive, 6,877 kbytes can be used as a cache.
Cheetah 10K.6 FC Product Manual, Rev. B11
The buffer can be divided into logical segments (using Mode Select Page 08h, byte 13) from which data is read
and to which data is written.
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
command is retrieved from the buffer, if possible, before any disc access is initiated. If cache operation is not
enabled, the buffer (still segmented with the 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 the explanation provided with the information about Mode Page 02h (disconnect/
reconnect control) in the
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.
Fibre Channel Interface Manual
Fibre Channel Interface Manual
.
), data requested by the host with a read
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 wrap-around capability of the individual segments greatly enhances the cache’s overall performance, allowing a wide range of user-selectable configurations. The drive supports operation of any integer
number of segments from 1 to 32. Divide the 6,877 Kbytes in the buffer by the number of segments to get the
segment size in bytes; then divide by the sector size to get the number of sectors per segment, any partial sectors remaining are not used. Default is 3 segments.
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.
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
12Cheetah 10K.6 FC Product Manual, Rev. B
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 generated.
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.
Table 15 shows the mode default settings for the drive.
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).
During a prefetch operation, the drive crosses a cylinder boundary to fetch more data only if Mode parameters
page 08h, byte 2, bit 4 is set to 1 (Discontinuity--DISC bit).
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
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 10K.6 FC Product Manual, Rev. B13
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
Seek error rate
Read Error Rates
Recovered Data
Unrecovered Data
Miscorrected Data
Interface error rate
1
Less than 10 errors in 10
Less than 10 errors in 10
Less than 1 sector in 10
Less than 1 sector in 10
Less than 1 error in 10
Less than 1 error in 10
(see Section 9.6.4, "Differential PECL input." on page 61)
MTBF1,200,000 hours
Service life5 years
Preventive maintenanceNone required
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 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."
• The drive has been formatted with the FC-AL Format command.
• Errors caused by media defects or host system failures are excluded from error rate computations.
• Assume random data.
8
seeks
12
bits transferred (OEM default settings)
15
bits transferred
21
bits transferred
12
bits transferred with minimum receive eye
14
bits transferred with typical receive eye
5.1.0.1Interface 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.
5.1.1Environmental interference
When evaluating systems operation under conditions of electromagnetic interference (EMI), the performance
of the drive within the system is considered acceptable if the drive does not generate an unrecoverable condition.
An unrecoverable error, or condition, is defined as one that:
• is not detected and corrected by the drive itself
• is not detected from the error or fault status provided through the drive or FC-AL interface
• is not recovered by normal drive or system recovery procedures without operator intervention
5.1.2Write 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 that cannot be corrected within two attempts
at writing the record with a read verify after each attempt (excluding media defects).
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 (15h) is reported with a Medium error (3h) or Hardware error (4h) reported in the
14Cheetah 10K.6 FC Product Manual, Rev. B
Sense Key. This is an unrecoverable seek error. Unrecoverable seek errors are classified as failures for MTBF
calculations. Refer to the
Fibre Channel Interface Manual
, part number 77767496, for Request Sense informa-
tion.
5.2Reliability and service
You can enhance the reliability of Cheetah 10K.6 FC disc drives by ensuring that the drive receives adequate
cooling. Section 6.0 provides recommended air-flow information, temperature measurements, and other information, which you can use to enhance the service life of the drive.
5.2.1Mean time between failure (MTBF)
The production disc drive achieves an MTBF of 1,200,000
hours when operated in an environment that
ensures the case temperatures specified in Section 6.3.1 are not exceeded. Short-term excursions up to the
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 Section Figure 12., "Environmental limits".
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 6.3.1 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.
5.2.3Service life
The drive has a useful service life of five 5 years. Depot repair or replacement of major parts is permitted during the lifetime.
5.2.4Service philosophy
Special equipment is required to repair the drive HDA. To achieve the above service life, repairs must be performed only at a properly equipped and staffed Seagate service and repair facility. Troubleshooting and repair
of PCBs in the field is not recommended because of the extensive diagnostic equipment required for effective
servicing. There are not spare parts available for this drive. The drive warranty is voided if the HDA is opened.
5.2.5Service tools
No special tools are required for site installation or recommended for site maintenance. Refer to Section 5.2.4.
The depot repair philosophy of the drive precludes the necessity for special tools. Field repair of the drive is not
practical because users cannot purchase individual parts for the drive.
Cheetah 10K.6 FC Product Manual, Rev. B15
5.2.6Hot plugging the drive
Inserting and removing the drive on the FC-AL will interrupt loop operation. The interruption occurs when the
receiver of the next device in the loop must synchronize to a different input signal. FC error detection mechanisms, character sync, running disparity, word sync, and CRC are able to detect any error. Recovery is initiated
based on the type of error.
The disc drive defaults to the FC-AL Monitoring state, Pass-through state, when it is powered-on by switching
the power or hot plugged. The control line to an optional port bypass circuit (external to the drive), defaults to
the Enable Bypass state. If the bypass circuit is present, the next device in the loop will continue to receive the
output of the previous device to the newly inserted device. If the bypass circuit is not present, loop operation is
temporarily disrupted until the next device starts receiving the output from the newly inserted device and
regains synchronization to the new input.
The Pass-through state is disabled while the drive performs self test of the FC interface. The control line for an
external port bypass circuit remains in the Enable Bypass state while self test is running. If the bypass circuit is
present, loop operation may continue. If the bypass circuit is not present, loop operation will be halted while the
self test of the FC interface runs.
When the self test completes successfully, the control line to the bypass circuit is disabled and the drive enters
the FC-AL Initializing state. The receiver on the next device in the loop must synchronize to output of the newly
inserted drive.
If the self-test fails, the control line to the bypass circuit remains in the Enable Bypass state.
Note.It is the responsibility of the systems integrator to assure that no temperature, energy, voltage hazard,
or ESD potential hazard is presented during the hot connect/disconnect operation. Discharge the static
electricity from the drive carrier prior to inserting it into the system.
Caution. The drive motor must come to a complete stop prior to changing the plane of operation. This time is
required to insure data integrity.
5.2.7S.M.A.R.T.
S.M.A.R.T. is an acronym for Self-Monitoring Analysis and Reporting Technology. This technology is intended
to recognize conditions that indicate imminent drive failure and is designed to provide sufficient warning of a
failure to allow you to back up the data before an actual failure occurs.
Note.The drive’s firmware monitors specific attributes for degradation over time but can’t predict instanta-
neous drive failures.
Each monitored attribute has been selected to monitor a specific set of failure conditions in the operating performance of the drive and the thresholds are optimized to minimize “false” and “failed” predictions.
Controlling S.M.A.R.T.
The operating mode of S.M.A.R.T. is controlled by the DEXCPT and PERF bits on the Informational Exceptions
Control mode page (1Ch). Use the DEXCPT bit to enable or disable the S.M.A.R.T. feature. Setting the DEXCPT bit disables all S.M.A.R.T. functions. When enabled, S.M.A.R.T. collects on-line data as the drive performs
normal read and write operations. When the PERF bit is set, the drive is considered to be in “On-line Mode
Only” and will not perform off-line functions.
You can measure off-line attributes and force the drive to save the data by using the Rezero Unit command.
Forcing S.M.A.R.T. resets the timer so that the next scheduled interrupt is in two hours.
You can interrogate the drive through the host to determine the time remaining before the next scheduled measurement and data logging process occurs. To accomplish this, issue a Log Sense command to log page 0x3E.
This allows you to control when S.M.A.R.T. interruptions occur. Forcing S.M.A.R.T. with the RTZ command
resets the timer.
Performance impact
S.M.A.R.T. attribute data is saved to the disc so that the events that caused a predictive failure can be recreated. The drive measures and saves parameters once every two hours subject to an idle period on the FC-AL
16Cheetah 10K.6 FC Product Manual, Rev. B
bus. The process of measuring off-line attribute data and saving data to the disc is uninterruptable. The maximum on-line only processing delay is summarized below:
Maximum processing delay
S.M.A.R.T. delay times
On-line only delay
DEXCPT = 0, PERF = 1
50 milliseconds
Fully-enabled delay
DEXCPT = 0, PERF = 0
milliseconds
300
Reporting control
Reporting is controlled by the MRIE bits in the Informational Exceptions Control mode page (1Ch). Subject to
the reporting method, the firmware will issue to the host an 01-5Dxx sense code. The error code is preserved
through bus resets and power cycles.
Determining rate
S.M.A.R.T. monitors the rate at which errors occur and signals a predictive failure if the rate of degraded errors
increases to an unacceptable level. To determine rate, error events are logged and compared to the number of
total operations for a given attribute. The interval defines the number of operations over which to measure the
rate. The counter that keeps track of the current number of operations is referred to as the Interval Counter.
S.M.A.R.T. measures error rates. All errors for each monitored attribute are recorded. A counter keeps track of
the number of errors for the current interval. This counter is referred to as the Failure Counter.
Error rate is the number of errors per operation. The algorithm that S.M.A.R.T. uses to record rates of error is to
set thresholds for the number of errors and their interval. If the number of errors exceeds the threshold before
the interval expires, the error rate is considered to be unacceptable. If the number of errors does not exceed
the threshold before the interval expires, the error rate is considered to be acceptable. In either case, the interval and failure counters are reset and the process starts over.
Predictive failures
S.M.A.R.T. signals predictive failures when the drive is performing unacceptably for a period of time. The firmware keeps a running count of the number of times the error rate for each attribute is unacceptable. To accomplish this, a counter is incremented each time the error rate is unacceptable and decremented (not to exceed
zero) whenever the error rate is acceptable. If the counter continually increments such that it reaches the predictive threshold, a predictive failure is signaled. This counter is referred to as the Failure History Counter.
There is a separate Failure History Counter for each attribute.
5.2.8Drive Self Test (DST)
Drive Self Test (DST) is a technology designed to recognize drive fault conditions that qualify the drive as a
failed unit. DST validates the functionality of the drive at a system level.
There are two test coverage options implemented in DST:
1. Extended test
2. Short text
The most thorough option is the extended test that performs various tests on the drive and scans every logical
block address (LBA) of the drive. The short test is time-restricted and limited in length—it does not scan the
entire media surface, but does some fundamental tests and scans portions of the media.
If DST encounters an error during either of these tests, it reports a fault condition. If the drive fails the test,
remove it from service and return it to Seagate for service.
5.2.8.1DST Failure Definition
The drive will present a “diagnostic failed” condition through the self-tests results value of the diagnostic log
page if a functional failure is encountered during DST. The channel and servo parameters are not modified to
test the drive more stringently, and the number of retries are not reduced. All retries and recovery processes
are enabled during the test. If data is recoverable, no failure condition will be reported regardless of the number
of retries required to recover the data.
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