Seagate ST936701SS manual Start/stop time, Prefetch/multi-segmented cache control, Cache operation

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4.3Start/stop time

The drive accepts the commands listed in the SAS Interface Manual less than 3 seconds after DC power has been applied.

If the drive receives a NOTIFY (ENABLE SPINUP) primitive through either port and has not received a START STOP UNIT command with the START bit equal to 0, the drive becomes ready for normal operations within 20 seconds (excluding the error recovery procedure).

If the drive receives a START STOP UNIT command with the START bit equal to 0 before receiving a NOTIFY (ENABLE SPINUP) primitive, the drive waits for a START STOP UNIT command with the START bit equal to 1. After receiving a START STOP UNIT command with the START bit equal to 1, the drive waits for a NOTIFY (ENABLE SPINUP) primitive. After receiving a NOTIFY (ENABLE SPINUP) primitive through either port, the drive becomes ready for normal operations within 20 seconds (excluding the error recovery procedure).

If the drive receives a START STOP UNIT command with the START bit and IMMED bit equal to 1 and does not receive a NOTIFY (ENABLE SPINUP) primitive within 5 seconds, the drive fails the START STOP UNIT command.

The START STOP UNIT command may be used to command the drive to stop the spindle. Stop time is 30 sec- onds (maximum) from removal of DC power. There is no power control switch on the drive.

4.4Prefetch/multi-segmented cache control

The drive provides a prefetch (read look-ahead) and multi-segmented cache control algorithms that in many cases can enhance system performance. Cache refers to the drive buffer storage space when it is used in cache operations. To select this feature, the host sends the Mode Select command with the proper values in the applicable bytes in page 08h. Prefetch and cache operations are independent features from the standpoint that each is enabled and disabled independently using the Mode Select command; however, in actual opera- tion, the prefetch feature overlaps cache operation somewhat as described in sections 4.5.1 and 4.5.2.

All default cache and prefetch mode parameter values (Mode Page 08h) for standard OEM versions of this drive family are given in Table 19.

4.5Cache operation

Note. Refer to the SAS Interface Manual for more detail concerning the cache bits.

Of the 8,192 kbytes physical buffer space in the drive, approximately 6,900 kbytes can be used as a cache. The buffer can be divided into logical segments (using Mode Select Page 08h, byte 13) from which data is read and to which data is written.

The drive keeps track of the logical block addresses of the data stored in each segment of the buffer. If the cache is enabled (see RCD bit in the SAS Interface Manual), data requested by the host with a read command is retrieved from the buffer, if possible, before any disc access is initiated. If cache operation is not enabled, the buffer (still segmented with the required number of segments) is still used, but only as circular buffer segments during disc medium read operations (disregarding Prefetch operation for the moment). That is, the drive does not check in the buffer segments for the requested read data, but goes directly to the medium to retrieve it. The retrieved data merely passes through some buffer segment on the way to the host. On a cache miss, all data transfers to the host are in accordance with buffer-full ratio rules. On a cache hit, the drive ignores the buffer- full ratio rules. See the explanation provided with the information about Mode Page 02h (disconnect/reconnect control) in the SAS Interface Manual.

The following is a simplified description of the prefetch/cache operation:

Case A—read command is received and the first logical block is already in the cache:

1.Drive transfers to the initiator the first logical block requested plus all subsequent contiguous logical blocks that are already in the cache. This data may be in multiple segments.

Savvio SAS Product Manual, Rev. D

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Contents ST973401SS ST936701SS Savvio SASPage Contents Interface requirements Defect and error managementInstallation Seagate Technology support servicesList of Figures Page Savvio family disc drive ScopeSavvio SAS Product Manual, Rev. D Electromagnetic susceptibility Applicable standards and reference documentationStandards Electromagnetic compatibilityKorean MIC Electromagnetic complianceElectromagnetic compliance for the European Union Australian C-TickSAS Interface Manual Reference documentsSavvio SAS Product Manual, Rev. D General description Media description Standard featuresPerformance Programmable drive capacity Factory-installed accessoriesReliability Formatted capacitiesUser-installed accessories Factory-installed optionsAccess time Performance characteristicsInternal drive characteristics Seek performance characteristicsGeneral performance characteristics Format command execution time for 512-byte sectors minutesPrefetch/multi-segmented cache control Start/stop timeCache operation Caching write data Prefetch operation Savvio SAS Product Manual, Rev. D Unrecoverable Errors Reliability specificationsError rates Recoverable ErrorsPreventive maintenance Reliability and serviceSeek errors Interface errorsPerformance impact Hot plugging the drive4 S.M.A.R.T Controlling S.M.A.R.TThermal monitor Reporting controlDetermining rate Predictive failuresImplementation Temperature Log Page 0Dh Parameter Code DescriptionDrive Self Test DST DST failure definitionShort test Function Code 001b State of the drive prior to testingInvoking DST Short and extended testsShipping Product warrantyLog page entries AbortProduct repair and return information ST973401SS DC power requirements Physical/electrical specificationsAC power requirements DC power requirementsGeneral DC power requirement notes ST936701SS DC power requirementsST936701SS Gbit mode Amps +5V +12V Power sequencingConducted noise immunity Current profilesTypical ST973401SS drive +12V current profile Typical ST936701SS drive +12V current profile ST973401SS in 3 Gbit operation Power dissipationST973401SS in 1.5 Gbit operation ST936701SS in 1.5 Gbit operation ST936701SS in 3 Gbit operationEnvironmental limits TemperatureRelative humidity Shock and vibration Effective altitude sea levelShock Recommended mounting Package size Packaged/product weight Drop heightVibration Air cleanlinessCorrosive environment Acoustics Mounting configuration dimensions Mechanical specificationsSavvio SAS Product Manual, Rev. D Drive internal defects/errors Defect and error managementDrive error recovery procedures SAS system errors Drive orientation InstallationAir flow CoolingGrounding Drive mountingSavvio SAS Product Manual, Rev. D Interface requirements SAS featuresDual port support Commands supported by Savvio SAS family drive Scsi commands supportedCommand name Command code Supported Commands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Commands supported by Savvio SAS family drive Bytes Data hex Mode Sense dataInquiry data Savvio inquiry dataPage DEF CHG Savvio SAS Product Manual, Rev. D Miscellaneous status Miscellaneous operating features and conditionsMiscellaneous features Supported Feature or conditionSAS physical interface Datum B Section C C Section a a Pin descriptions Physical characteristicsConnector requirements Electrical descriptionSAS pin descriptions Pin Signal name Signal typeSAS transmitters and receivers Signal characteristics Receive eye mask General interface characteristicsCharacteristic Units Gbps Eye masks Eye masks overviewReveive tolerance eye mask Jitter tolerance masksFrequency 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 CjtpatImpedance requirements Sheet 2 Transmitter characteristicsElectrical TxRx connections = -5,437dB Tctf ISI loss example at 1.5 Gbps Receiver characteristicsSavvio SAS Product Manual, Rev. D Technical Support Seagate Technology support servicesInternet Presales SupportData Recovery Services Authorized Service Centers Warranty ServiceData Recovery Services Call Center Toll-free Direct dial Numerics IndexPage 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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