Seagate ST9146802SS Start/stop time, Prefetch/multi-segmented cache control, Cache operation

Page 23

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 20 sec- onds (maximum) from removal of DC power. SCSI stop time is 20 seconds. 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 16 Mbytes physical buffer space in the drive, approximately 13,000 kbytes can be used as a cache. The buffer is divided into logical segments 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 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. All data transfers to the host are in accordance with 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 all of the requested logical blocks are already in the cache:

1. Drive transfers the requested logical blocks to the initiator.

Savvio 10K.2 SAS Product Manual, Rev. B

13

Page 22 Page 24
Image 23
Page 22 Page 24
Contents Savvio 10K.2 SAS Page Savvio 10K.2 SAS Page Revision Date Revision status summary sheetPage Contents Interface requirements Defect and error managementInstallation Seagate Technology support servicesSavvio 10K.2 SAS disc drive List of FiguresPage Savvio 10K.2 SAS disc drive ScopeSavvio 10K.2 SAS Product Manual, Rev. B Electromagnetic susceptibility Applicable standards and reference documentationStandards Electromagnetic compatibilityKorean MIC Electromagnetic complianceElectromagnetic compliance for the European Union Australian C-TickEuropean Union Restriction of Hazardous Substances RoHS Reference documentsSavvio 10K.2 SAS Product Manual, Rev. B General description Performance Standard featuresMedia description Programmable drive capacity Factory-installed accessoriesReliability Formatted capacitiesFactory-installed options Access time Performance characteristicsInternal drive characteristics Seek performance characteristicsGeneral performance characteristics Format command execution time for 512-byte sectors minutesCache operation Start/stop timePrefetch/multi-segmented cache control Prefetch operation Caching write dataPage Savvio 10K.2 SAS Product Manual, Rev. B Unrecoverable Errors Reliability specificationsError rates Recoverable ErrorsPreventive maintenance Reliability and serviceSeek errors Interface errorsMilliseconds 4 S.M.A.R.TControlling S.M.A.R.T Performance impactThermal 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 ST9146802SS DC power requirements Physical/electrical specificationsAC power requirements DC power requirementsST973402SS Gbit mode Amps ST973402SS DC power requirementsGeneral DC power requirement notes +5V +12V Power sequencingConducted noise immunity Current profilesST973402SS current profile ST973402SS in 3 Gbit operation Power dissipationST9146802SS in 3 Gbit operation Environmental limits TemperatureShock Relative humidityEffective altitude sea level Shock and vibrationRecommended mounting Package size Packaged/product weight Drop heightCorrosive environment Air cleanlinessVibration Acoustics Mounting configuration dimensions Mechanical specificationsSavvio 10K.2 SAS Product Manual, Rev. B Drive error recovery procedures Defect and error managementDrive internal defects/errors Page Background Media Scan SAS system errorsIdle Read After Write Media Pre-ScanDeferred Auto-Reallocation Drive orientation InstallationAir flow CoolingGrounding Drive mountingSavvio 10K.2 SAS Product Manual, Rev. B Interface requirements SAS featuresDual 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 Bytes Data hex Mode Sense dataInquiry data Savvio inquiry dataPage Mode Data Header 08 8b b9 98 00 00 02 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 descriptionReady LED Out Signal characteristicsPower SAS transmitters and receiversEye masks Eye masks overview LED drive signalDifferential signals General interface characteristicsJitter tolerance masks Receive eye maskFrequency 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 CjtpatElectrical TxRx connections Transmitter characteristicsImpedance requirements Sheet 2 = -5,437dB Tctf ISI loss example at 1.5 Gbps Receiver characteristicsPresales Support Seagate Technology support servicesWarranty Service Internet MySeagate Spp.seagate.comData Recovery Services Data Recovery Services Authorized Service CentersToll-free support numbers FAX services-All Europe toll callCall center Presales and Technical Support Warranty Service Seagate Service Centers Numerics IndexPage SAS See also cooling Page Seagate Technology LLC
Related manuals
Manual 84 pages 36.64 Kb

ST973402SS, ST9146802SS specifications

The Seagate ST973402SS and ST9146802SS are high-performance, enterprise-grade hard drives designed to meet the demanding needs of data-intensive applications. These drives are part of Seagate's Savvio and Barracuda product lines, aimed specifically at businesses and institutions requiring reliability, speed, and efficiency in storage solutions.

The ST973402SS is a 73GB, 2.5-inch hard drive, while the ST9146802SS offers a larger capacity of 146GB. Both models utilize a 10,000 RPM spindle speed, which significantly enhances their ability to handle fast data read and write operations. This speed ensures reduced latency and improved overall performance, making them ideal for environments where rapid access to data is crucial.

One of the standout features of these drives is their support for Serial Attached SCSI (SAS) interface. SAS technology provides a point-to-point connection, which allows for increased data transfer rates compared to traditional SATA drives. The ST973402SS and ST9146802SS are capable of transferring data at speeds of up to 600 MB/s, facilitating efficient data transfers in enterprise systems.

In terms of reliability, both models offer advanced features designed to improve data integrity and durability. They are built to withstand high workloads, with an annualized workload rate of up to 550 TB per year. This makes them well-suited for applications like databases and transactional storage, where sustained performance is required. Additionally, the drives feature Seagate’s PowerFit technology, which optimizes performance while minimizing power consumption.

To enhance data security, the drives come equipped with self-encrypting technology, ensuring that sensitive data is protected through hardware-based encryption. This is particularly important in environments where data breaches can lead to significant operational impacts.

The drives are also designed to operate efficiently in terms of thermal management, featuring robust heat dissipation capabilities. This helps to maintain optimal performance levels while prolonging the lifespan of the drives.

Overall, the Seagate ST973402SS and ST9146802SS are robust and reliable hard drives that cater to the needs of enterprise environments, combining high capacity, exceptional speed, advanced security features, and energy efficiency to help businesses maintain and manage large volumes of data effectively. With their proven performance and innovative technologies, these drives are well-equipped to support a wide range of applications in modern data centers.
Top Page Image Contents