Seagate ST3400755SS manual Defect and error management, Drive internal defects/errors

Page 39

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.

Cheetah NS SAS Product Manual, Rev. B

33

Page 38 Page 40
Image 39
Page 38 Page 40
Contents ST3400755SS Cheetah NS SASPage Contents Interface requirements Defect and error managementInstallation Seagate Technology support servicesTypical ST3400755SS drive +5V and +12V current profiles List of FiguresCheetah NS SAS Product Manual, Rev. B Scope Cheetah NS SAS Product Manual, Rev. B Electromagnetic susceptibility Standards, compliance and reference documentsStandards Electromagnetic compatibilityCompliance Reference documents Cheetah NS SAS Product Manual, Rev. B General description Reliability Standard featuresMedia description PerformanceST3400755SS Factory-installed optionsFormatted capacities Programmable drive capacityCheetah NS SAS Product Manual, Rev. B Seek performance Performance characteristicsInternal drive characteristics Access timeFormat command execution time minutes General performance characteristicsStart/stop time Prefetch/multi-segmented cache control Cache operationCaching write data Prefetch operation Unrecoverable 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 impactTemperature Log Page 0Dh Predictive failuresThermal monitor Invoking 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 ShippingCheetah NS SAS Product Manual, Rev. B ST3400755SS DC power requirements Physical/electrical specificationsAC power requirements DC power requirementsCurrent profiles General DC power requirement notesPower sequencing Conducted noise immunityTypical ST3400755SS drive +5V and +12V current profiles Power dissipationEnvironmental limits TemperatureShock Relative humidityEffective altitude sea level Shock and vibrationRecommended mounting Package size Packaged/product weight Drop heightCorrosive environment Air cleanlinessVibration AcousticsChina Restriction of Hazardous Substances RoHS Directive X表示该部件（于同类物品程度上）所含的危险和有毒物质中国RoHS MCV标准所定义的门槛值。Physical dimensions Mechanical specificationsCheetah NS SAS Product Manual, Rev. B Defect and error management Drive internal defects/errorsDrive error recovery procedures 77.87 SAS system errors Background Media ScanMedia Pre-Scan Idle Read After Write Deferred Auto-ReallocationDrive orientation InstallationAir flow CoolingGrounding Drive mountingCheetah NS SAS Product Manual, Rev. B Interface requirements SAS featuresDual port support Scsi commands supported Commands supported by Cheetah NS SAS family drivesCommand name Command code Supported Commands supported by Cheetah NS SAS family drives Commands supported by Cheetah NS SAS family drives Commands supported by Cheetah NS SAS family drives Mode Sense data Inquiry dataCheetah NS SAS inquiry data Bytes Data hex Page Mode Pages 2.1 ST3400755SS Mode Sense dataMiscellaneous status Miscellaneous operating features and conditionsMiscellaneous features Supported Feature or conditionSAS physical interface Datum B Connector requirements Physical characteristicsSAS pin descriptions Pin Signal name Signal typeElectrical description Pin descriptionsReady LED Out Signal characteristicsPower SAS transmitters and receiversEye masks Eye masks overview LED drive signalDifferential signals General interface characteristicsNormalized time in UI Receive eye maskJitter tolerance masks Absolute amplitudeFrequency in kHz Peak-toSinusoidal JitterSignal characteristica Units Gbps Transmitter signal characteristicsGbps m, n Deterministic jitterq Receiver signal characteristicsSignal characteristic Units Gbps Maximum allowable jitterImpedance requirements Sheet 1 Impedance specificationsReceiver jitter tolerance Compliant jitter test pattern CjtpatTransmitter characteristics Impedance requirements Sheet 2Electrical TxRx connections = -5,437dB Shows the zero-length test load Receiver characteristics Cheetah NS SAS Product Manual, Rev. B Technical Support Seagate Technology support servicesInternet Presales SupportWarranty Service Data Recovery Services Authorized Service CentersData Recovery Services Call Center Toll-free Direct dial Numerics IndexPage SAS See also cooling
Top Page Image Contents