Seagate ST973401SS, ST936701SS manual Caching write data

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2.When a requested logical block is reached that is not in any cache segment, the drive fetches it and any remaining requested logical block addresses from the disc and puts them in a segment of the cache. The drive transfers the remaining requested logical blocks from the cache to the host in accordance with the Mode Select Disconnect/Reconnect parameters, page 02h.

3.If the prefetch feature is enabled, refer to section 4.5.2 for operation from this point.

Case B—A Read command requests data, and the first logical block is not in any segment of the cache:

1.The drive fetches the requested logical blocks from the disc and transfers them into a segment, and then from there to the host in accordance with the Mode Select Disconnect/Reconnect parameters, page 02h.

2.If the prefetch feature is enabled, refer to section 4.5.2 for operation from this point.

During a prefetch, the drive crosses a cylinder boundary to fetch data only if the Discontinuity (DISC) bit is set to 1 in bit 4 of byte 2 of the Mode Select parameters page 08h. Default is zero for bit 4.

Each cache segment is actually a self-contained circular buffer whose length is an integer number of logical blocks. The wrap-around capability of the individual segments greatly enhances the cache’s overall perfor- mance, allowing a wide range of user-selectable configurations. The drive supports operation of any integer number of segments from 1 to 16. Divide the 6,900 Kbytes in the buffer by the number of segments to get the segment size. Default is 3 segments.

Note. The size of each segment is not reported by Mode Sense command page 08h, bytes 14 and 15. The value 0XFFFF is always reported regardless of the actual size of the segment. Sending a size specification using the Mode Select command (bytes 14 and 15) does not set up a new segment size. If the STRICT bit in Mode page 00h (byte 2, bit 1) is set to one, the drive responds as it does for any attempt to change an unchangeable parameter.

4.5.1Caching write data

Write caching is a write operation by the drive that makes use of a drive buffer storage area where the data to be written to the medium is stored while the drive performs the Write command.

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 19 shows the mode default settings for the drive.

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Savvio SAS Product Manual, Rev. D

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Contents Savvio SAS ST973401SS ST936701SSPage Contents Defect and error management InstallationSeagate Technology support services Interface requirementsList of Figures Page Scope Savvio family disc driveSavvio SAS Product Manual, Rev. D Applicable standards and reference documentation StandardsElectromagnetic compatibility Electromagnetic susceptibilityElectromagnetic compliance Electromagnetic compliance for the European UnionAustralian C-Tick Korean MICReference documents SAS Interface ManualSavvio SAS Product Manual, Rev. D General description Performance Standard featuresMedia description Factory-installed accessories ReliabilityFormatted capacities Programmable drive capacityFactory-installed options User-installed accessoriesPerformance characteristics Internal drive characteristicsSeek performance characteristics Access timeFormat command execution time for 512-byte sectors minutes General performance characteristicsCache operation Start/stop timePrefetch/multi-segmented cache control Caching write data Prefetch operation Savvio SAS Product Manual, Rev. D Reliability specifications Error ratesRecoverable Errors Unrecoverable ErrorsReliability and service Seek errorsInterface errors Preventive maintenanceHot plugging the drive 4 S.M.A.R.TControlling S.M.A.R.T Performance impactReporting control Determining ratePredictive failures Thermal monitorTemperature Log Page 0Dh Parameter Code Description Drive Self Test DSTDST failure definition ImplementationState of the drive prior to testing Invoking DSTShort and extended tests Short test Function Code 001bProduct warranty Log page entriesAbort ShippingProduct repair and return information Physical/electrical specifications AC power requirementsDC power requirements ST973401SS DC power requirementsST936701SS Gbit mode Amps ST936701SS DC power requirementsGeneral DC power requirement notes Power sequencing Conducted noise immunityCurrent profiles +5V +12VTypical ST973401SS drive +12V current profile Typical ST936701SS drive +12V current profile ST973401SS in 1.5 Gbit operation Power dissipationST973401SS in 3 Gbit operation ST936701SS in 3 Gbit operation ST936701SS in 1.5 Gbit operationRelative humidity TemperatureEnvironmental limits Shock Effective altitude sea levelShock and vibration Package size Packaged/product weight Drop height Recommended mountingCorrosive environment Air cleanlinessVibration Acoustics Mechanical specifications Mounting configuration dimensionsSavvio SAS Product Manual, Rev. D Drive error recovery procedures Defect and error managementDrive internal defects/errors SAS system errors Installation Drive orientationCooling Air flowDrive mounting GroundingSavvio SAS Product Manual, Rev. D SAS features Interface requirementsDual port support Command name Command code Supported Scsi commands supportedCommands 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 Mode Sense data Inquiry dataSavvio inquiry data Bytes Data hexPage DEF CHG Savvio SAS Product Manual, Rev. D Miscellaneous operating features and conditions Miscellaneous featuresSupported Feature or condition Miscellaneous statusSAS physical interface Datum B Section C C Section a a Physical characteristics Connector requirementsElectrical description Pin descriptionsSAS transmitters and receivers Pin Signal name Signal typeSAS pin descriptions Signal characteristics General interface characteristics Characteristic Units GbpsEye masks Eye masks overview Receive eye maskJitter tolerance masks Reveive tolerance eye maskPeak-to SinusoidalJitter Frequency in kHzTransmitter signal characteristics Signal characteristica Units GbpsReceiver signal characteristics Signal characteristic Units GbpsMaximum allowable jitter Gbps m, n Deterministic jitterqImpedance specifications Receiver jitter toleranceCompliant jitter test pattern Cjtpat Impedance requirements Sheet 1Electrical TxRx connections Transmitter characteristicsImpedance requirements Sheet 2 = -5,437dB Tctf Receiver characteristics ISI loss example at 1.5 GbpsSavvio SAS Product Manual, Rev. D Seagate Technology support services InternetPresales Support Technical SupportData Recovery Services Call Center Toll-free Direct dial Warranty ServiceData Recovery Services Authorized Service Centers Index NumericsPage SAS See also cooling
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ST936701SS, ST973401SS specifications

The Seagate ST936701SS and ST973401SS are high-performance enterprise hard drives designed for optimal data storage solutions in demanding environments. Both models belong to Seagate's Savvio series, which is renowned for its reliability and efficiency. These drives are tailored for critical applications such as database management, data warehousing, and online transaction processing.

The ST936701SS comes with a storage capacity of 36.4 GB, while the ST973401SS offers a larger capacity of 73.4 GB. This variance allows users to choose the drive that best suits their storage needs without compromising performance. Both drives utilize a 2.5-inch form factor, making them compact and suitable for high-density storage configurations.

A key feature of these drives is their impressive rotational speed of 10,000 RPM, which enhances data access times and improves overall system responsiveness. This speed allows for reduced latency and faster data transfer rates, critical for applications that require quick retrieval of large datasets.

In terms of technology, these drives utilize the Serial Attached SCSI (SAS) interface, which is favored in enterprise settings for its reliability and speed. SAS provides better performance than traditional SATA drives, particularly when dealing with high workloads, as it supports multiple concurrent connections and higher data throughput.

The ST936701SS and ST973401SS are also equipped with advanced features such as Seagate's Native Command Queuing (NCQ), which optimizes the order in which read and write commands are executed. This results in improved performance under multi-tasking conditions, essential for enterprise servers managing multiple requests simultaneously.

Additionally, both drives incorporate features aimed at enhancing data integrity and reliability. They support End-to-End Data Protection and are designed to endure the rigors of continuous operation, with MTBF (Mean Time Between Failures) ratings that bolster their reputation for durability.

Energy efficiency is another notable characteristic, as both drives are designed to reduce power consumption without sacrificing performance. This is particularly important in enterprise environments where power management contributes to lower operational costs.

In conclusion, the Seagate ST936701SS and ST973401SS drives are robust, reliable storage solutions tailored for enterprise applications. With their high performance, advanced technology features, and capacity options, they provide organizations with the scalability and efficiency required in today’s data-driven landscape. Whether it's for critical data management tasks or high-access applications, these drives stand out as a solid choice for any enterprise storage strategy.
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