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Seagate ST973451SS, ST936751SS manual Idle Read After Write

Models: ST936751SS ST973451SS

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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

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Seagate ST973451SS, ST936751SS manual Idle Read After Write

Contents

ST973451SS ST936751SS Savvio 15K SASPRODUCT MANUAL 100407739 Rev. BMarch 09/15/06 Revision status summary sheetRev. A Initial releaseSavvio 15K SAS Product Manual, Rev. B 5.0 Reliability specifications Contents4.0 Performance characteristics 6.0 Physical/electrical specifications10.0 Seagate Technology support services 7.0 Defect and error management8.0 Installation 9.0 Interface requirementsList of Figures Page 1.0 Scope Savvio 15K SAS Product Manual, Rev. B 2.1.1 Electromagnetic compatibility 2.0 Applicable standards and reference documentation2.1 Standards 2.1.1.1 Electromagnetic susceptibilityAustralian C-Tick 2.1.2 Electromagnetic complianceElectromagnetic compliance for the European Union Korean MICSpecification for Acoustic Test Requirement and Procedures 2.2 Reference documentsSCSI Commands Reference Manual SAS Interface Manual 2.1.3 European Union Restriction of Hazardous Substances RoHSSavvio 15K SAS Product Manual, Rev. B 3.0 General description 3.2 Media description 3.1 Standard features3.3 Performance 3.5 Formatted capacities 3.7 Factory-installed accessories3.4 Reliability 3.6 Programmable drive capacity3.8 Options 4.2 Seek performance characteristics 4.0 Performance characteristics4.1 Internal drive characteristics 4.2.1 Access time Gen 2.0 LP dataGeneral performance characteristics 4.2.2 Format command execution time4.2.3 4.4 Prefetch/multi-segmented cache control 4.3 Start/stop time4.5 Cache operation 4.5.1 Caching write data 4.5.2 Prefetch operation5.1.1 Recoverable Errors 5.0 Reliability specifications5.1 Error rates 5.1.2 Unrecoverable Errors5.1.4 Interface errors 5.2 Reliability and service5.1.3 Seek errors 5.2.2 Preventive maintenanceFully-enabled delay Maximum processing delayOn-line only delay 5.2.4 S.M.A.R.T5.2.5 Thermal monitor Temperature Log Page 0DhPredictive failures Parameter Code5.2.6.2 Implementation 5.2.6.2.1 State of the drive prior to testing5.2.6.1 DST failure definition 5.2.6.2.2 Invoking DSTExtended test Function Code 010b 5.2.7 Product warrantyShort test Function Code 001b 5.2.6.2.4 Log page entriesShipping Product repair and return informationSavvio 15K SAS Product Manual, Rev. B 6.2 DC power requirements 6.0 Physical/electrical specifications6.1 AC power requirements Table 2 ST973451SS DC power requirementsST936751SS DC power requirements General DC power requirement notes6.2.3 Current profiles 6.2.2 Power sequencing6.2.1 Conducted noise immunity Figure 1. Typical ST973451SS current profileSavvio 15K SAS Product Manual, Rev. B Figure 2. Typical ST936751SS current profileST973451SS in 3 Gbit operation 6.3 Power dissipationST973451SS in 1.5 Gbit operation ST936751SS in 1.5 Gbit operation ST936751SS in 3 Gbit operation12 Vo lt A 6.4.1 Temperature 6.4 Environmental limits6.4.2 Relative humidity 6.4.4 Shock and vibration 6.4.3 Effective altitude sea level6.4.4.1 Shock Drop height Packaged/product weightPackage size Figure 8. Recommended mounting6.4.4.2 Vibration 6.4.5 Air cleanliness6.4.6 Corrosive environment 6.4.7 Acoustics 6.4.8 Electromagnetic susceptibility6.5 Mechanical specifications Figure 9. Mounting configuration dimensions7.1 Drive internal defects/errors 7.0 Defect and error management7.2 Drive error recovery procedures Maximum recovery time per 7.3 SAS system errorsTable 4 Read and write retry count maximum recovery times Maximum recovery time per7.5 Media Pre-Scan 7.4 Background Media Scan7.6 Deferred Auto-Reallocation 7.7 Idle Read After Write 8.0 Installation 8.1 Drive orientation8.2 Cooling Figure 11. Air flow8.3 Drive mounting 8.4 GroundingSavvio 15K SAS Product Manual, Rev. B 9.1.1 task management functions 9.1 SAS features9.0 Interface requirements SAS task management functions supported9.2 Dual port support 9.3 SCSI commands supported Commands supported by Savvio SAS family driveCommands supported by Savvio SAS family drive continued Commands supported by Savvio SAS family drive continued Commands supported by Savvio SAS family drive continued Savvio inquiry data 9.3.2 Mode Sense data9.3.1 Inquiry data Bytes4. Changeable values CHG = Changeable bits indicates if default value is changeable3. Current values Savvio 15K SAS Product Manual, Rev. BMODE DATA HEADER 03 fa 00 10 00 00 00 BLOCK DESCRIPTOR Savvio 15K SAS Product Manual, Rev. B Miscellaneous features 9.4 Miscellaneous operating features and conditionsMiscellaneous status 9.4.1 SAS physical interface Figure 12. Physical interfaceFigure 13. SAS device plug dimensions C OF DATUM B LFigure 14. SAS device plug dimensions detail TO DATUM A9.4.4 Electrical description 9.4.2 Physical characteristics9.4.3 Connector requirements 9.4.5 Pin descriptionsTX Transmitter 100 TY Table 13 SAS pin descriptions9.4.6 SAS transmitters and receivers Differential Transfer MediumLED drive signal 9.5 Signal characteristics9.4.7 Power 9.5.2 Differential signals9.5.2.1 Eye masks 9.5.2.1.1 Eye masks overview Table 16 General interface characteristicsCharacteristic 9.5.2.1.2 Receive eye mask9.5.2.1.3 Jitter tolerance masks Figure 17. Reveive tolerance eye maskPeak-to 9.5.2.2 Transmitter signal characteristicsTable 17 Transmitter signal characteristics sinusoidalTable 18 Receiver signal characteristics Table 17 Transmitter signal characteristics9.5.2.3 Receiver signal characteristics a All tests in this table shall be performed with zero-length test load shown in figure9.5.2.3.2 Receiver jitter tolerance 9.5.2.3.1 JitterTable 19 Maximum allowable jitter 9.5.2.3.3 Compliant jitter test pattern CJTPAT9.5.2.3.4 Impedance specifications Table 21 Impedance requirements Sheet 1 ofTable 21 Impedance requirements Sheet 2 of 9.5.2.4.1 Transmitter characteristics9.5.2.4 Electrical TxRx connections = -10, 884dB = -5, 437dBTx+ TCTF Tx Figure 21. ISI loss example at 3.0 Gbps Figure 20. Zero-length test loadFigure 22. ISI loss example at 1.5 Gbps 9.5.2.5 Receiver characteristics Savvio 15K SAS Product Manual, Rev. B Internet 10.0 Seagate Technology support servicesSeagate Service Centers Presales SupportEurope, the Middle East and Africa Support Services Customer Service OperationsUSA/Canada/Latin America support services Asia/Pacific Support ServicesNumerics IndexPage Page See also cooling Page 920 Disc Drive, Scotts Valley, California 95066-4544, USA Seagate Technology LLCPublication Number 100407739, Rev. B, Printed in USA