Seagate ST936751SS, ST973451SS manual Defect and error management, Drive internal defects/errors

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7.0Defect and error management

Seagate continues to use innovative technologies to manage defects and errors. These technologies are designed to increase data integrity, perform drive self-maintenance, and validate proper drive operation.

SCSI defect and error management involves drive internal defect/error management and SAS system error considerations (errors in communications between the initiator and the drive). In addition, Seagate provides the following technologies used to increase data integrity and drive reliability:

•Background Media Scan (see Section 7.4)

•Media Pre-Scan (see Section 7.5)

•Deferred Auto-Reallocation (see Section 7.6)

•Idle Read After Write (see Section 7.7)

The read error rates and specified storage capacities are not dependent on host (initiator) defect management routines.

7.1Drive internal defects/errors

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.

Details of the SCSI commands supported by the drive are described in the SAS Interface Manual. Also, more information on the drive Error Recovery philosophy is presented in the SAS Interface Manual.

7.2Drive error recovery procedures

When an error occurs during drive operation, the drive, if programmed to do so, performs error recovery proce- dures to attempt to recover the data. The error recovery procedures used depend on the options previously set in the Error Recovery Parameters mode page. Error recovery and defect management may involve using sev- eral SCSI commands described in the SAS Interface Manual. The drive implements selectable error recovery time limits required in video applications.

The error recovery scheme supported by the drive provides a way 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 using 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 using the Read Retry Count or Write Retry Count bytes in the Error Recovery mode page.

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Contents 100407739 Rev. B Savvio 15K SASPage Revision status summary sheet Savvio 15K SAS Product Manual, Rev. B Contents Interface requirements Defect and error managementInstallation Seagate Technology support servicesList of Figures Page Scope Savvio 15K SAS Product Manual, Rev. B Electromagnetic susceptibility Applicable standards and reference documentationStandards Electromagnetic compatibilityKorean MIC Electromagnetic complianceElectromagnetic compliance for the European Union Australian C-TickEuropean Union Restriction of Hazardous Substances RoHS Reference documentsSavvio 15K SAS Product Manual, Rev. B General description Media description Standard featuresPerformance Programmable drive capacity Factory-installed accessoriesReliability Formatted capacitiesOptions Access time Gen 2.0 LP data Performance characteristicsInternal drive characteristics Seek performance characteristicsGeneral performance characteristics Format command execution timePrefetch/multi-segmented cache control Start/stop timeCache operation Prefetch operation Caching write dataUnrecoverable Errors Reliability specificationsError rates Recoverable ErrorsPreventive maintenance Reliability and serviceSeek errors Interface errorsReporting control 4 S.M.A.R.TControlling S.M.A.R.T Performance impactParameter Code Description Temperature Log Page 0DhPredictive failures Thermal monitorInvoking 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 ShippingSavvio 15K SAS Product Manual, Rev. B ST973451SS DC power requirements Physical/electrical specificationsAC power requirements DC power requirementsGeneral DC power requirement notes ST936751SS DC power requirementsConducted noise immunity Power sequencingCurrent profiles Typical ST936751SS current profile ST973451SS in 3 Gbit operation Power dissipationST973451SS in 1.5 Gbit operation ST936751SS in 1.5 Gbit operation ST936751SS in 3 Gbit operationEnvironmental limits TemperatureRelative humidity Shock and vibration Effective altitude sea levelShock Recommended mounting Vibration Air cleanlinessCorrosive environment Acoustics Mounting configuration dimensions Mechanical specificationsDrive internal defects/errors Defect and error managementDrive error recovery procedures SAS system errors Media Pre-Scan Background Media ScanDeferred Auto-Reallocation Idle Read After Write Drive orientation InstallationAir flow CoolingGrounding Drive mountingSavvio 15K SAS Product Manual, Rev. B Interface requirements SAS featuresDual port support Commands supported by Savvio SAS family drive Scsi commands supportedCommands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Inquiry data Mode Sense dataSavvio inquiry data Page Mode Data Header 04 45 dc cc 00 00 02 Miscellaneous features Miscellaneous operating features and conditionsMiscellaneous status SAS physical interface Datum B Section C C Section a a Pin descriptions Physical characteristicsConnector requirements Electrical descriptionSAS transmitters and receivers SAS pin descriptionsSignal characteristics Eye masks Eye masks overview General interface characteristicsReceive eye mask Z1 OP Jitter tolerance masksJitter Transmitter signal characteristicsPeak-to SinusoidalReceiver signal characteristics Receiver jitter tolerance Maximum allowable jitterCompliant jitter test pattern Cjtpat Impedance requirements Sheet 1 Impedance specificationsImpedance requirements Sheet 2 Transmitter characteristicsElectrical TxRx connections = -5,437dB Shows the zero-length test load Receiver characteristics Savvio 15K SAS Product Manual, Rev. B Technical Support Seagate Technology support servicesInternet Presales SupportData Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call Center Toll-free Direct dial Numerics IndexPage SAS See also cooling
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