Seagate ST336607FC, ST3146807FC, ST373307FC manual Prefetch operation

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Cheetah 10K.6 FC Product Manual, Rev. B

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 15 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 disc immediately beyond that which was requested by a Read command are retrieved and stored in the buffer for immediate transfer from the buffer to the host on subsequent Read commands that request those logical blocks (this is true even if cache opera- tion 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.

Since data that is prefetched replaces data already in some buffer segments, the host can limit the amount of prefetch data to optimize system performance. The Max Prefetch field (bytes 8 and 9) limits the amount of prefetch. The drive does not use the Prefetch Ceiling field (bytes 10 and 11).

During a prefetch operation, the drive crosses a cylinder boundary to fetch more data only if Mode parameters page 08h, byte 2, bit 4 is set to 1 (Discontinuity--DISC bit).

When prefetch (read look-ahead) is enabled (enabled by DRA = 0), it operates under the control of ARLA (Adaptive Read Look-Ahead). If the host uses software interleave, ARLA enables prefetch of contiguous blocks from the disc when it senses that a prefetch hit will likely occur, even if two consecutive read operations were not for physically contiguous blocks of data (e.g. “software interleave”). ARLA disables prefetch when it decides that a prefetch hit will not likely occur. If the host is not using software interleave, and if two sequential read operations are not for contiguous blocks of data, ARLA disables prefetch, but as long as sequential read oper- ations request contiguous blocks of data, ARLA keeps prefetch enabled.

4.5.3Optimizing cache performance for desktop and server applications

Desktop and server applications require different drive caching operations for optimal performance. This means it is difficult to provide a single configuration that meets both of these needs. In a desktop environment, you want to configure the cache to respond quickly to repetitive accesses of multiple small segments of data without taking the time to “look ahead” to the next contiguous segments of data. In a server environment, you want to configure the cache to provide large volumes of sequential data in a non-repetitive manner. In this case, the ability of the cache to “look ahead” to the next contiguous segments of sequential data is a good thing.

The Performance Mode (PM) bit controls the way the drive switches the cache buffer into different modes of segmentation. In “server mode” (PM bit = 0), the drive can dynamically change the number of cache buffer seg- ments as needed to optimize the performance, based on the command stream from the host. In “desktop mode” (PM bit = 1), the number of segments is maintained at the value defined in Mode Page 8, Byte 13, at all times. For additional information about the PM bit, refer to the Unit Attention Parameters page (00h) of the Mode Sense command (1Ah) in the Fibre Channel Interface Product Manual, part number 77767496.

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Contents Page Page Page Page Revision status summary sheet Revision Date Writer/Engineer Sheets AffectedPage Contents Seagate Technology support services Defect and error managementInstallation Interface requirementsList of Figures Cheetah 10K.6 FC Product Manual, Rev. B ViiPage Scope Cheetah 10K.6 FC family disc driveCheetah 10K.6 FC Product Manual, Rev. B Applicable standards and reference documentation Taiwanese Bsmi Australian C-TickKorean MIC Reference documentsGeneral description Cheetah 10K.6 FC disc drivePerformance Standard featuresMedia description ReliabilityUser-installed accessories Factory-installed accessoriesFactory-installed options Unformatted and formatted capacitiesCheetah 10K.6 FC Product Manual, Rev. B Seek performance characteristics Access time Performance characteristicsInternal drive characteristics Format command execution time in minutesPrefetch/multi-segmented cache control General performance characteristicsStart/stop time Cache operationCaching write data Prefetch operation Reliability specifications Service life Reliability and servicePreventive maintenance Service philosophyControlling S.M.A.R.T 7 S.M.A.R.TPerformance impact Determining rate MillisecondsReporting control Predictive failuresInvoking DST State of the drive prior to testingImplementation Short and extended testsAbort Product warrantyLog page entries ShippingDC power requirements Physical/electrical specificationsAC power requirements General DC power requirement notesCurrent profiles Power sequencingConducted noise immunity +5V +12VTypical ST373307FC drive +12V current profile Typical ST3146807FC drive +5V current profile Typical ST373307FC drive +5V current profile Power dissipation ST3146807FC ST373307FCTemperature Cheetah 10K.6 FC Product Manual, Rev. B ST336607FCShock and vibration Relative humidityEffective altitude sea level ShockPackage size Packaged/product weight Drop height Recommended mounting Cheetah 10K.6 FC Product Manual, Rev. B Vibration Air cleanlinessAcoustics Mechanical specifications Mounting configuration dimensionsDrive internal defects/errors Defect and error managementDrive error recovery procedures Read and write retry count maximum recovery times Read retry Maximum recovery time per Write retryFC-AL system errors Maximum recovery time perDrive ID/option selection InstallationLED connections Drive orientation 1 J6 connector requirementsDrive Front CoolingDrive mounting Air flowGrounding Interface requirements FC-AL featuresFibre Channel link service frames Fibre Channel task management functionsFibre Channel port login NPort login Plogi payload BytesNPort Login Accept ACC payload Bytes Fibre Channel Process LoginFibre Channel Process Login Accept Process Login Plri payloadFibre Channel fabric login Fabric Login Flogi payload BytesFabric Login Accept ACC payload Bytes Accept or NPort Login when sending frames to an initiatorFC-AL options supported Fibre Channel Arbitrated Loop optionsDual port support Option SupportedSupported commands Command code Command name Supported commands Command code Supported Command nameRead descriptor mode Cheetah 10K.6 FC Product Manual, Rev. B Cheetah 10K.6 FC inquiry data Mode Sense dataCheetah 10K.6 FC Product Manual, Rev. B Inquiry data Bytes Data hexCheetah 10K.6 FC Product Manual, Rev. B DEF DEF CHG Cheetah 10K.6 FC Product Manual, Rev. B Supported Feature or condition Miscellaneous operating features and conditionsMiscellaneous features Miscellaneous statusPhysical characteristics Physical descriptionConnector requirements Part description Positions Part number FeaturesPin descriptions Pin Signal name Signal typeFC-SCA pin descriptions FC-AL transmitters and receivers PowerFault LED Out Active LED OutMotor start controls Enable port bypass signals11 SEL6 through SEL0 ID lines Parallel Enclosure Services Interface ESI Setting Hex Dec SettingArbitrated loop physical address Alpa values LED driver signals Signal characteristicsTTL input characteristics Device control codesTransmit eye diagram Differential Pecl inputEye diagram data values Link rate GHzPresales Support Seagate Technology support services Online ServicesAutomated Services Technical SupportUSA/Canada/Latin America Support Services Customer Service CSOEuropean Support Services Asia/Pacific Support Services Africa/Middle East Support ServicesCall Center Toll-free Direct dial Cheetah 10K.6 FC Product Manual, Rev. B Index FC-AL Cheetah 10K.6 FC Product Manual, Rev. B Plogi Cheetah 10K.6 FC Product Manual, Rev. B Cheetah 10K.6 FC Product Manual, Rev. B
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ST336607FC, ST373307FC, ST3146807FC specifications

The Seagate ST373307FC, ST3146807FC, and ST336607FC are robust hard disk drives designed for enterprise environments where reliability and performance are critical. Each model offers distinct features suited to various data storage needs, reflecting Seagate's commitment to innovation in storage technology.

The ST373307FC is a 73GB Fibre Channel hard drive that operates at 15,000 RPM, making it exceptionally fast for read and write operations. This drive employs a 4GB cache, enhancing its performance by allowing quicker access to frequently used data. With a 3.5-inch form factor, the ST373307FC is built for high-density environments, delivering reliable access to data. Its Fibre Channel interface supports high-speed connections, essential for data-intensive applications like databases and virtualization.

Next in line, the ST3146807FC offers a capacity of 146GB, also operating at 15,000 RPM. This drive features an 8GB cache, which significantly improves its data transfer rates, making it ideal for transactional workloads. The ST3146807FC is engineered to minimize latency and maximize throughput, ensuring that enterprises can access critical data swiftly and efficiently. Additionally, its rugged construction is designed to withstand the demands of continuous operation, providing peace of mind for businesses with strict uptime requirements.

Lastly, the ST336607FC has a substantial storage capacity of 300GB and shares the 15,000 RPM operational speed that characterizes this high-performance line. With a similar 8GB cache as the ST3146807FC, it offers excellent performance for read-intensive and write-heavy applications. The ST336607FC is also designed with enhanced thermal management features, supporting cooler operations in densely packed server environments. This model is particularly suited for applications such as data warehousing and online transaction processing, where speed and reliability are paramount.

Each of these drives utilizes advanced technologies like Native Command Queuing (NCQ), which optimizes the order of read and write requests. These features, combined with Seagate's reputation for durability and performance, make the ST373307FC, ST3146807FC, and ST336607FC excellent choices for enterprise applications requiring high-speed data access and exceptional reliability. In environments where data integrity and uptime are critical, these drives provide the robust performance necessary to meet demanding storage needs.
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