Seagate ST336705LW/LC, ST318405LW/LC manual Defect and error management, Drive internal defects

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Cheetah 36XL Product Manual, Rev. E

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7.0Defect and error management

The drive, as delivered, complies with this specification. The read error rate and specified storage capacity are not dependent upon use of defect management routines by the host (initiator).

Defect and error management in the SCSI system involves the drive internal defect/error management and SCSI systems error considerations (errors in communications between Initiator and the drive). Tools for use in designing a defect/error management plan are briefly outlined in this section, with references to other sections where further details are given.

7.1Drive internal defects

During the initial drive format operation at the factory, media defects are identified, tagged as being unusable, and their locations recorded on the drive primary defects list (referred to as the “P” list and also as the ETF defect list). At factory format time, these known defects are also reallocated, that is, reassigned to a new place on the medium and the location listed in the defects reallocation table. The “P” list is not altered after factory formatting. Locations of defects found and reallocated during error recovery procedures after drive shipment are listed in the “G” list (defects growth list). The “P” and “G” lists may be referenced by the initiator using the Read Defect Data command (see the SCSI Interface Product Manual, part number 75789509).

7.2Drive error recovery procedures

Whenever an error occurs during drive operation, the drive, if programmed to do so, performs error recovery procedures to attempt to recover the data. The error recovery procedures used depend on the options previ- ously set up in the error recovery parameters mode page. Error recovery and defect management may involve the use of several SCSI commands, the details of which are described in the SCSI Interface Product Manual. The drive implements selectable error recovery time limits such as are required in video applications. For addi- tional information on this, refer to the Error Recovery Page table in the SCSI Interface Product Manual, which describes the Mode Select/Mode Sense Error Recovery parameters.

The error recovery scheme supported by the drive provides a means to control the total error recovery time for the entire command in addition to controlling the recovery level for a single LBA. The total amount of time spent in error recovery for a command can be limited via the Recovery Time Limit bytes in the Error Recovery Mode Page. The total amount of time spent in error recovery for a single LBA can be limited via the Read Retry Count or Write Retry Count bytes in the Error Recovery Mode Page.

The drive firmware error recovery algorithms consist of 11 levels for read recoveries and 15 levels for writes.

Table 3 equates the Read and Write Retry Count with the maximum possible recovery time for read and write recovery of individual LBAs. The times given do not include time taken to perform reallocations, if reallocations are performed. Reallocations are performed when the ARRE bit (for reads) or AWRE bit (for writes) is one, the RC bit is zero, and the Recovery Time Limit for the command has not yet been met. Time needed to perform reallocation is not counted against the Recovery Time Limit.

The Read Continuous (RC) bit, when set to one, requests the disc drive to transfer the requested data length without adding delays (for retries or ECC correction) that may be required to insure data integrity. The disc drive may send erroneous data in order to maintain the continuous flow of data. The RC bit should only be used when data integrity is not a concern and speed is of utmost importance. If the Recovery Time Limit or retry count is reached during error recovery, the state of the RC bit is examined. If the RC bit is set, the drive will transfer the unrecovered data with no error indication and continue to execute the remaining command. If the RC bit is not set, the drive will stop data transfer with the last good LBA, and report a “Check Condition, Unrecovered Read Error.”

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Contents Cheetah 36XL Family ST336705LW/LC ST318405LW/LC ST39205LW/LC Page Cheetah 36XL Family ST336705LW/LC ST318405LW/LC ST39205LW/LC Page Revision Date Writer/Engineer Sheets Affected Revision status summary sheetPage Contents Interface requirements Defect and error managementInstallation Seagate Technology support servicesCheetah 36XL Product Manual, Rev. E Vii List of FiguresPage Cheetah 36XL family drive ST336705LC shown ScopeCheetah 36XL Product Manual, Rev. E Applicable standards and reference documentation Taiwanese Bsmi Australian C-TickKorean MIC General description Cheetah 36XL family drive Reliability Cheetah 36XL Product Manual, Rev. E Standard featuresMedia characteristics PerformanceProgrammable drive capacity Factory installed accessoriesOptions factory installed Formatted capacitiesPerformance characteristics Prefetch/multi-segmented cache control Ultra2 Scsi Ultra160 ScsiStart/stop time Caching write data Cache operationPrefetch operation Cheetah 36XL Product Manual, Rev. E Cheetah 36XL Product Manual, Rev. E Reliability specifications Service philosophy Reliability and servicePreventive maintenance Service lifeControlling S.M.A.R.T 7 S.M.A.R.TPredictive failures Performance impactReporting control Determining rateInvoking DST State of the drive prior to testingDST Failure Definition ImplementationLog page entries Product warrantyShort test Function Code 001b Extended test Function Code 010bProduct repair and return information Cheetah 36XL Product Manual, Rev. E DC power requirements Physical/electrical specificationsAC power requirements 3 12 V Current profile Power sequencingConducted noise immunity Typical ST336705 drive +12 V current profile Typical ST39205 drive +12 V current profile TypicalST318405 drive +5 V current profile Power dissipation ST336705 Os per Second Cheetah 36XL Product Manual, Rev. E ST318405Environmental limits TemperatureST39205 Shock Relative humidityEffective altitude sea level Shock and vibrationPackage size Packaged/product weight Drop height Recommended mounting Acoustics Air cleanlinessVibration LW mounting configuration dimensions LC mounting configuration dimensions Drive internal defects Defect and error managementDrive error recovery procedures Scsi systems errors Drive ID/option select header InstallationConfigure drive options FormattingDo not install jumpers retain cover J5 jumper header on LW model only J2 option select header Does not apply to LC models Cheetah 36XL Product Manual, Rev. E Function descriptionGrounding Drive orientationCooling Drive mountingScsi interface messages supported Interface requirementsScsi interface commands supported Cheetah 36XL Product Manual, Rev. E Commands supported by Cheetah 36XL family drive Inquiry Vital Product data Mode Sense dataCheetah 36XL Product Manual, Rev. E Mode Sense Data Cheetah 36XL Product Manual, Rev. E Mode sense data, ST318405 values Bytes Cheetah 36XL Product Manual, Rev. E Mode sense data, ST39205 values Bytes Cheetah 36XL Product Manual, Rev. E Condition/features supported Physical interface DC cable and connector2 REQ/ACK offset Pin Power Scsi interface cable requirements Scsi interface physical descriptionST336705LC, ST318405LC and ST39205LC Mating connectorsMating connectors for LW model drives Mating connectors for LC model drivesScsi ID Right-angle to Pcba connectorsNonshielded 68 pin Scsi device connector used on LW drives Nonshielded 80 pin Scsi SCA-2 connector, used on LC drives GND +DBP1 Charge 68Cheetah 36XL Product Manual, Rev. E Multimode-SE and LVD alternatives Multimode signalsElectrical description Input characteristics Output characteristicsLC drives General cable characteristicsTerminator requirements Terminator power LW drives Low voltage differential I/O circuitsDisc drive Scsi timing Drive activity remote LED signal status Cheetah 36XL Product Manual, Rev. E Technical Support Seagate Technology support services Online ServicesAutomated Services Presales SupportEuropean Support Services Customer Service CSOUSA/Canada/Latin America Support Services Call Center Toll-free Direct dial Africa/Middle East Support ServicesAsia/Pacific Support Services Cheetah 36XL Product Manual, Rev. E Index Symbols Cheetah 36XL Product Manual, Rev. E LED PCB System chassis Page