Seagate ST31000640SS, ST3750630SS, ST3500620SS manual Prefetch operation

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If read caching is enabled (RCD=0), then data written to the medium is retained in the cache to be made avail- able for future read cache hits. The same buffer space and segmentation is used as set up for read functions. The buffer segmentation scheme is set up or changed independently, having nothing to do with the state of RCD. When a write command is issued, if RCD=0, the cache is first checked to see if any logical blocks that are to be written are already stored in the cache from a previous read or write command. If there are, the respective cache segments are cleared. The new data is cached for subsequent Read commands.

If the number of write data logical blocks exceed the size of the segment being written into, when the end of the segment is reached, the data is written into the beginning of the same cache segment, overwriting the data that was written there at the beginning of the operation; however, the drive does not overwrite data that has not yet been written to the medium.

If write caching is enabled (WCE=1), then the drive may return Good status on a write command after the data has been transferred into the cache, but before the data has been written to the medium. If an error occurs while writing the data to the medium, and Good status has already been returned, a deferred error will be gen- erated.

The Synchronize Cache command may be used to force the drive to write all cached write data to the medium. Upon completion of a Synchronize Cache command, all data received from previous write commands will have been written to the medium.

Table 9.3.2.1 shows the mode default settings for the drive.

4.5.2Prefetch operation

If the Prefetch feature is enabled, data in contiguous logical blocks on the disk immediately beyond that which was requested by a Read command are retrieved and stored in the buffer for immediate transfer from the buf- fer to the host on subsequent Read commands that request those logical blocks (this is true even if cache operation is disabled). Though the prefetch operation uses the buffer as a cache, finding the requested data in the buffer is a prefetch hit, not a cache operation hit.

To enable Prefetch, use Mode Select page 08h, byte 12, bit 5 (Disable Read Ahead - DRA bit). DRA bit = 0 enables prefetch.

The drive does not use the Max Prefetch field (bytes 8 and 9) or the Prefetch Ceiling field (bytes 10 and 11).

When prefetch (read look-ahead) is enabled (enabled by DRA = 0), the drive enables prefetch of contiguous blocks from the disk when it senses that a prefetch hit will likely occur. The drive disables prefetch when it decides that a prefetch hit is not likely to occur.

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Barracuda ES.2 SAS Product Manual, Rev. E

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Contents Barracuda ES.2 SAS ST31000640SS ST3750630SS ST3500620SSPage Contents Seagate Technology support services Defect and error managementInstallation Interface requirementsScope Barracuda ES.2 SAS Product Manual, Rev. E Electromagnetic compatibility Standards, compliance and reference documentsStandards Electromagnetic susceptibilityCompliance Reference documents Barracuda ES.2 SAS Product Manual, Rev. E General description Barracuda ES.2 drive illustrationPerformance Standard featuresMedia description ReliabilityFactory-installed options Formatted capacitiesProgrammable drive capacity Barracuda ES.2 SAS Product Manual, Rev. E Access time Performance characteristicsInternal drive characteristics Seek performanceFormat command execution time minutes General performance characteristicsStart/stop time Prefetch/multi-segmented cache control Cache operationCaching write data Prefetch operation Recoverable Errors Reliability specificationsError rates Unrecoverable ErrorsInterface errors Reliability and serviceSeek errors Preventive maintenancePerformance impact 4 S.M.A.R.TControlling S.M.A.R.T Reporting controlTemperature Log Page 0Dh Predictive failuresThermal monitor Implementation State of the drive prior to testingDST failure definition Invoking DSTExtended test Function Code 010b Product warrantyShort test Function Code 001b Log page entriesShipping Product repair and return informationBarracuda ES.2 SAS Product Manual, Rev. E DC power requirements Physical/electrical specificationsAC power requirements ST31000640SS DC power requirementsST3750630SS DC power requirements ST3500620SS DC power requirementsConducted noise immunity General DC power requirement notesPower sequencing Current profilesTypical ST31000640SS drive +5V and +12V current profiles Power dissipation Typical ST3500620SS drive +5V and +12V current profilesBarracuda ES.2 SAS Product Manual, Rev. E Temperature a. Operating Environmental limitsShock and vibration Relative humidityEffective altitude sea level a. Operating ShockPackage size Packaged/product weight Drop height Acoustics Air cleanlinessVibration a. Operating-normal Corrosive environmentX表示该部件（于同类物品程度上）所含的危险和有毒物质超出中国RoHS MCV标准所定义的门槛值。 Mechanical specifications Physical dimensionsDefect and error management Drive internal defects/errorsDrive error recovery procedures 108.29 SAS system errors Background Media ScanMedia Pre-Scan Deferred Auto-Reallocation Idle Read After WriteInstallation Drive orientationCooling Air flowDrive mounting GroundingBarracuda ES.2 SAS Product Manual, Rev. E SAS features Interface requirementsDual port support Scsi commands supported Commands supported by Barracuda ES.2 SAS family drivesCommands supported by Barracuda ES.2 SAS family drives Commands supported by Barracuda ES.2 SAS family drives Commands supported by Barracuda ES.2 SAS family drives Mode Sense data Inquiry dataPage 2.1 ST31000640SS Mode Sense data Mode Pages2.2 ST3750630SS Mode Sense data 2.3 ST3500620SS Mode Sense data Miscellaneous operating features and conditions Miscellaneous featuresMiscellaneous status SAS physical interface Datum B Physical characteristics Connector requirementsElectrical description Pin descriptionsSAS pin descriptions SAS transmitters and receivers Signal characteristicsPower Ready LED OutGeneral interface characteristics LED drive signalDifferential signals Eye masks Eye masks overviewReceive eye mask Jitter tolerance masksJitter Peak-toSinusoidal Frequency in kHzTransmitter signal characteristics Receiver signal characteristics Maximum allowable jitterCompliant jitter test pattern Cjtpat Impedance specificationsReceiver jitter tolerance Impedance requirements Sheet 1Transmitter characteristics Impedance requirements Sheet 2Electrical TxRx connections = -5, 437dB Shows the zero-length test load Receiver characteristics Barracuda ES.2 SAS Product Manual, Rev. E Presales Support Seagate Technology support servicesInternet Technical SupportWarranty Service Data Recovery Services Authorized Service CentersData Recovery Services Call Center Toll-free Direct dial Index Page SAS See also cooling Page Seagate Technology LLC

ST31000640SS, ST3500620SS, ST3750630SS specifications

Seagate has been a leading name in the storage industry for decades, and its range of enterprise-class hard drives showcases advanced technologies and robust performance. The Seagate ST3750630SS, ST3500620SS, and ST31000640SS are three notable models that cater to the demands of data centers and enterprises. Each model is designed with specific features that enhance reliability and efficiency, making them suitable for various applications.

The Seagate ST3750630SS is a 750GB 15K RPM Serial Attached SCSI (SAS) drive. It boasts a high-performance architecture that allows for fast data transfer rates, making it ideal for high-load environments such as transaction processing and video streaming. This drive features an MTBF of 1.6 million hours, ensuring minimal downtime due to failures. It also employs advanced error recovery and data protection mechanisms, including error correction codes (ECC), to maintain data integrity.

Meanwhile, the ST3500620SS offers a capacity of 500GB with a spinning speed of 15K RPM as well. This drive utilizes the SAS interface, providing users with improved bandwidth and connectivity compared to traditional SATA drives. The ST3500620SS is designed with a focus on high availability, featuring a robust design that supports multiple workloads simultaneously. Its quick access times enhance overall system performance, making it a preferred choice for high-performance computing applications.

The ST31000640SS is another enterprise-class offering, delivering 1TB of storage capacity. Like its counterparts, this drive operates at 15K RPM and utilizes the SAS interface, facilitating fast data processing and retrieval. It also incorporates a dual-port design which allows for redundancy and failover capabilities. This feature is critical in enterprise environments where data access and uptime are paramount. The drive's design is optimized for durability and longevity, best suited for environments that require 24/7 operation.

All three Seagate drives feature advanced technologies such as dual-stage actuators and thermal write technology, ensuring improved read and write performance, along with reduced power consumption. Additionally, they are built to endure the rigors of enterprise workloads, including heavy I/O operations and high access demands.

In summary, the Seagate ST3750630SS, ST3500620SS, and ST31000640SS are exemplary models that reflect the company’s commitment to quality and performance in enterprise storage solutions. With their high speeds, reliability, and extensive features, these drives are well-equipped to meet the challenges of modern data-driven environments.
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