in the United States and/or other countries. Cheetah NS, 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 Technology® LLC, Cheetah NS FC (Fibre Channel) disc drives.
Cheetah NS FC drives support the Fibre Channel Arbitrated Loop and SCSI Fibre Channel Protocol specifica-
tions to the extent described in this manual. The Fibre Channel Interface Manual (part number 100293070)
describes the general Fibre Channel Arbitrated Loop characteristics of this and other Seagate Fibre Channel
drives.
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3
2.0Standards, compliance and reference documents
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, audi 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 8.4.
2.1Standards
The Cheetah NS FC family complies with Seagate standards as noted in the appropriate sections of this manual and the Seagate Fibre Channel Interface Manual, part number 100293070.
The Cheetah NS 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. 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. 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.
2.1.1.1Electromagn 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 Table 2, DC power requirements.
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Cheetah NS FC Product Manual, Rev. A
2.2Compliance
2.2.1Electromagn etic complia nce
Seagate uses an independent laboratory to confirm compliance with the directives/standards 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 th is Seag ate mo del comp lies with the dir ectives/st and ards, we cannot gu aran tee
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 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.
This drive has been tested and complies with the Electromagnetic Interference/Electromagnetic Susceptibiliity
(EMI/EMS) for Class B products.
Taiwanese BSMI
If this model has the Chin ese N ation al Standard (CNS) 13438 marking, it co mplies w ith Chi n ese Nationa l Standard (CNS) 13438 and meets the Electromagnetic Compatibility (EMC) Framework requirements of the Taiwanese Bureau of Standards, Metrology, and Inspection (BSMI).
Cheetah NS FC Product Manual, Rev. A
5
2.3Reference documents
Cheetah NS FC Installation GuideSeagate part number: 100457517
SCSI Commands Reference ManualSeagate part number: 100293068
Fibre Channel Interface ManualSeagate part number: 100293070
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.
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7
3.0General description
Cheetah NS FC drives provide high performance, high capacity data storage for a variety of systems including
engineering workstations, network servers, mainframes, and supercomputers. Cheetah NS FC drives support
4-Gbit Fibre Channel which can transfer data at up to 800 Mbytes per second and 1600 Mbytes per second in
dual-loop configurations.
Cheetah NS FC drives support the Fibre Channel Arbitrated Loop (FC-AL) and SCSI Fibre Channel Protocol
as described in the ANSI specifications, this document, and the Fibre Channel Interface Manual which
describes the general interface characteristics of this drive. Cheetah NS FC drives are classified as intelligent
peripherals and provide level 2 conformance (highest level) with the ANSI SCSI-1 standard.
Note.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 does not contain user-replaceable
parts. Opening the HDA for any reason voids your warranty.
Cheetah drives use a de dicated landing zone a t the innermost radius of the media to e liminate the p ossibility of
destroying or de grad i ng d at a b y l and ing in the data zone. Th e h eads autom atical ly go t o 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.
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.
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Cheetah NS FC Product Manual, Rev. A
3.1Standard featu re s
Cheetah NS FC drives have the following standard features:
• Perpendicular recording technology
• 4-Gbit Fibre Channel interfac e
• 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.
• Supports SCSI Enclosure Services through the interface connector
• Fibre Channel worldwide name uniquely identifies the drive and each port
• User-selectable logical block size (512, 520, 524, or 528 bytes per logical block)
• 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
• Embedded servo design
• Automatic shipping lock
• Self-diagnostics performed when power is applied to the drive
• Zone bit recording (ZBR)
• Vertical, horizontal, or top down mounting
• Dynamic spindle b rake
• 16 Mbyte data buffer (see Section 4.5).
• Reallocation of defects on command (Post Format)
3.2Media desc ription
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.
Cheetah NS FC Product Manual, Rev. A
9
3.3Performance
• Programmable multi-segmentable cache buffer
• 800 Mbytes/sec maximum instantaneous data transfers per port
• 10k RPM spindle. Average latency = 2.98 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.)
• 5-year warranty
3.5Formatted 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 desig ns 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 maximum available capacity at a given sector size, but the excess
capacity above the gu aran teed leve l w ill va ry betwe en 10K an d 15K fam ilie s and fr om g ener ation 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 forward compatibility takes precedence.
3.6Programmable 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 Commands R efere nce Manu al . Refer to the Param eter 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.
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Cheetah NS FC Product Manual, Rev. A
3.7Factory-installed options
Yo u may order the following items which are incorporated at the manufacturing facility d uring 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. 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 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-ins talle d accessorie s
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.
Cheetah NS FC Product Manual, Rev. A
11
4.0Performance characteristics
This section provides detailed information concerning performance-related characteristics and features of
Cheetah NS FC drives.
4.1Internal drive characteristics
ST3400755FCST3300955FC
Drive capacity*400.0300Gbytes (formatted, rounded off value)
Read/write data heads84
Tracks per surface (total)92,20092,200Tracks (user accessible)
Tracks per inch155,000155,000TPI
Peak bits per inch979k979kBPI
Areal density151.7151.7Gbits/inch
Internal data rate725 to 1,211725 to 1,211Mbits/sec (variable with zone)
Disc rotation speed10k10krpm
Avg rotational latency2.982.98msec
*One Gbyte equals one billion bytes when referring to hard drive capacity. Accessible capacity may vary depending on operating environment
and formatting.
4.2Seek performance
See Section 9.5, "FC-AL physical interface" on page 61 and the Fibre Channel Interface Manual (part number
77767496) for additional timing details.
2
4.2.1Access time
Not including controller overhead
ReadWrite
AverageTypical3.94.2
Single trackTypical0.350.52
Full stro keTypical6.87.5
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)
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Cheetah NS FC Product Manual, Rev. A
4.2.2Format command execution time (minutes)
ST3400755FCST3300955FC
Maximum (with verify)180140
Maximum (without verify)10080
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).
4.2.3General performance characteristics
Sustainable disc transfer rate*:
Minimum54 Mbytes/sec
Maximum97 Mbytes/sec
Fibre Channel Interface maximum instantaneous transfer rate800 Mbytes/sec* per port
(dual port = 1600 Mbytes/sec*)
Logical block sizes
Default is 512-byte data blocks
Sector sizes variable to 512, 520, 524 and 528 bytes.
Read/write consecutive sectors on a trackYes
Flaw reallocation performance impact (for flaws reallocated at f ormat time
using the spare sectors per sparing zone reallocation scheme.)
*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
4.3Start/stop time
The drive accepts the commands listed in the Fibre Channel Interface Manual less than 3 seconds after DC
power has been applied.
If the drive receives a NOTIFY (ENABLE SPINUP) primitive through either port and has not received a START
STOP UNIT command with the START bit equal to 0, the drive becomes ready for normal operations within 30
seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit equal to 0 before receiving a NOTIFY
(ENABLE SPINUP ) pri mitive, the drive waits for a S TART STOP UNIT com mand wi th th e START bit equal to 1.
After receiving a START STOP UNIT command with the START bit equal to 1, the drive waits for a NOTIFY
(ENABLE SPINUP) primitive. After receiving a NOTIFY (ENABLE S PINUP) primitive through either port, the
drive becomes ready for normal operations within 30 seconds (excluding the error recovery procedure).
If the drive receives a START STOP UNIT command with the START bit and IMMED bit equal to 1 and does
not receive a NOTIFY (ENABLE SPINUP) primitive within 5 seconds, the drive fails the START STOP UNIT
command.
The START ST OP UN IT comm and m ay be used to comm and the dr ive to st op the spi ndle. Stop time is 30 seconds (maximum) from removal of DC power.
There is no power control switch on the drive.
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13
4.4Prefetch /m ulti-segmen te d cache contro l
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 Section 9.3.2
4.5Cache operation
Note.Refer to the Fibre Ch anne l Interface Manual for more detail concerning the cache bits.
Of the 16 Mbytes physical buffer sp ace in the drive, approximately 13,000 kbytes can be used as a cache. The
buffer is divided into logical segments 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 FC Interface Manual ), data requested by the host with a read command
is retrieved from the buf fe r, if possible, before any disc access is initiated . If cach e oper ation is not en abled, the
buffer 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 i t. The retrieved data merely passes through some buf fer
segment on the way to the host. All data transfers to the host are in accordance with buffer-full ratio rules. See
the explanation p rovide d with th e i nfor matio n abo ut Mo de P age 02h ( disconne ct/reconnect control) in th e Fibre Channel Interface Manual.
The following is a simplified description of the prefetch/cache operation:
Case A—read command is received and all of the requested logical blocks are already in the cache:
1. Drive transfers the requested logical blocks to the initiator.
Case B—A Read command requests data, and at least one requested 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.
Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical
blocks. The drive dynamically creates and removes segments based on the workload. The wrap-around capability of the individual segments greatly enhances the cache’s overall performance.
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.
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Cheetah NS FC Product Manual, Rev. A
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 dat a logical blo cks excee d the size o f the segm ent b eing wr itten into, wh en th e en d of the
segment is reached, the data is written i nto the b eginning of the same cache segment, overwriting the dat a 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 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 17 and 18 show the mode default settings for these 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 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.
The drive does not use the Max Prefetch field (bytes 8 and 9) or the Prefetch Ceiling field (bytes 10 and 11).
When prefetch (read look-ahead) is enabled (enabled by DRA = 0), the drive enables prefetch of contiguous
blocks from the disc when it senses that a prefetch hit will likely occur. The drive disables prefetch when it
decides that a prefetch hit is not likely to occur.
Cheetah NS FC Product Manual, Rev. A
15
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
5.1Error rate s
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 Section 6.2
• 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.
Less than 10 errors in 108 seeks
Less than 10 errors in 1012 bits transferred (OEM default settings)
Less than 1 sector in 1016 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 69
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 o n-the-fly is not considered fo r purposes o f recov-
ered 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 1016 bits transferred. Unrecoverable Data Errors resulting from the same cause are treated as 1 error for that block.
16
Cheetah NS FC Product Manual, Rev. A
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 automaticall y perf orms an error recovery process. If the error recover y 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 108 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 disk 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 8.2 provides recommended air-flow information.
5.2.1Annualized Failure Rate (AFR) and Mean Time Between Failures (MTBF)
These drives shal l ach ieve an A FR of 0.62 % ( MTBF of 1,400,000 hours) w he n op erate d in an en vi ronm ent that
ensures the HDA case temperatures do not exceed the values specified in Section 6.4.1.
Operation at case temperatures outside the specifications in Section 6.4.1 may increase the AFR (decrease
the MTBF).
AFR and MTBF statistics are poplulation statistics that are not relevant to individual units. AFR and MTBF
specifications are based on the following assumptions for Enterprise Storage System environments:
• 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.
5.2.2Preventive mainte nan ce
No routine scheduled preventive maintenance is required.
5.2.3Hot 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 disp a rity, 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.
Cheetah NS FC Product Manual, Rev. A
17
The Pass-through state is disabled while the drive perfo rms 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 oper ation m ay con tinue. If the byp ass circ uit is not pres ent, loo p ope ration will be h alted 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 st a te. The receiver on the ne xt device i n the loo p must synch ronize t o outpu t 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 haz-
ard, 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 s t op pri or to ch anging the pl a ne of o pera tion. T his time is
required to insure data integrity.
5.2.4S.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 f irmwar e moni tor s specific attr ibutes for degr adatio n ove r tim e b ut can ’ t predi ct in sta nt a-
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” predi ctions.
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 Exce ptions
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 enab led, S .M. A.R.T. collects on -line d ata as the drive p erfor ms
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 th e host t o dete rmine the time remaining b efore the ne xt schedu l ed me asurement and d at a logg i ng p rocess occur s . To accomplish this, i ssue 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
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
42 milliseconds
Fully-enabled delay
DEXCP T = 0, PE R F = 0
163 milliseconds
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