Idle Read After Write | Seagate ST973451SS, ST936751SS instruction

7.7Idle Read After Write

Idle Read After Write (IRAW) utilizes idle time to verify the integrity of recently written data. During idle periods, no active system requests, the drive reads recently written data from the media and compares it to valid write command data resident in the drives data buffer. Any sectors that fail the comparison result in the invocation of a rewrite and auto-reallocation process. The process attempts to rewrite the data to the original location. If a verification of this rewrite fails, the sector is re-mapped to a spare location.

38	Savvio 15K SAS Product Manual, Rev. B

Image 46

Seagate ST973451SS, ST936751SS manual Idle Read After Write

Contents

Savvio 15K SAS 100407739 Rev. BPage Revision status summary sheet Savvio 15K SAS Product Manual, Rev. B Contents Seagate Technology support services Defect and error managementInstallation Interface requirements List of Figures Page Scope Savvio 15K SAS Product Manual, Rev. B Electromagnetic compatibility Applicable standards and reference documentationStandards Electromagnetic susceptibility Australian C-Tick Electromagnetic complianceElectromagnetic compliance for the European Union Korean MIC Reference documents European Union Restriction of Hazardous Substances RoHS Savvio 15K SAS Product Manual, Rev. B General description Media description Standard featuresPerformance Formatted capacities Factory-installed accessoriesReliability Programmable drive capacity Options Seek performance characteristics Performance characteristicsInternal drive characteristics Access time Gen 2.0 LP data Format command execution time General performance characteristics Prefetch/multi-segmented cache control Start/stop timeCache operation Caching write data Prefetch operation Recoverable Errors Reliability specificationsError rates Unrecoverable Errors Interface errors Reliability and serviceSeek errors Preventive maintenance Performance impact 4 S.M.A.R.TControlling S.M.A.R.T Reporting control Thermal monitor Temperature Log Page 0DhPredictive failures Parameter Code Description Implementation State of the drive prior to testingDST failure definition Invoking DST Extended test Function Code 010b Product warrantyShort test Function Code 001b Log page entries Shipping Product repair and return information Savvio 15K SAS Product Manual, Rev. B DC power requirements Physical/electrical specificationsAC power requirements ST973451SS DC power requirements ST936751SS DC power requirements General DC power requirement notes Conducted noise immunity Power sequencingCurrent profiles Typical ST936751SS current profile ST973451SS in 3 Gbit operation Power dissipationST973451SS in 1.5 Gbit operation ST936751SS in 3 Gbit operation ST936751SS in 1.5 Gbit operation Environmental limits TemperatureRelative humidity Shock and vibration Effective altitude sea levelShock Recommended mounting Vibration Air cleanlinessCorrosive environment Acoustics Mechanical specifications Mounting configuration dimensions Drive 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 Installation Drive orientation Cooling Air flow Drive mounting Grounding Savvio 15K SAS Product Manual, Rev. B SAS features Interface requirements Dual port support Scsi commands supported Commands supported by Savvio SAS family drive Commands 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 Electrical description Physical characteristicsConnector requirements Pin descriptions SAS pin descriptions SAS transmitters and receivers Signal characteristics Eye masks Eye masks overview General interface characteristicsReceive eye mask Jitter tolerance masks Z1 OP Sinusoidal Transmitter signal characteristicsPeak-to Jitter Receiver signal characteristics Receiver jitter tolerance Maximum allowable jitterCompliant jitter test pattern Cjtpat Impedance specifications Impedance requirements Sheet 1 Impedance requirements Sheet 2 Transmitter characteristicsElectrical TxRx connections = -5,437dB Shows the zero-length test load Receiver characteristics Savvio 15K SAS Product Manual, Rev. B Presales Support Seagate Technology support servicesInternet Technical Support Data Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call Center Toll-free Direct dial Index NumericsPage SAS See also cooling