Maxtor 6800 manual Cache Management, Buffer Segmentation, Read-Ahead Mode, Write Cache Stacking

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PRODUCTDESCRIPTION

Cache Management

Buffer Segmentation

The data buffer is organized into two segments: the data buffer and the micro controller scratch pad. The data buffer is dynamically allocated for read and write data depending on the commands received. A variable number of read and write buffers may exist at the same time.

Read-Ahead Mode

Normally, this mode is active. Following a read request, disk read-ahead begins on the first sector and continues sequentially until the allocated buffer is full. If a read request is received during the read-ahead operation, the buffer is examined to determine if the request is in the cache. If a cache hit occurs, read- ahead mode continues without interruption and the host transfer begins immediately.

Automatic Write Reallocation (AWR)

This feature is part of the write cache and reduces the risk of data loss during deferred write operations. If a disk error occurs during the disk write process, the disk task stops and the suspect sector is reallocated to a pool of alternate sectors located at the end of the drive. Following reallocation, the disk write task continues until it is complete.

Write Cache Stacking

Normally, this mode is active. Write cache mode accepts the host write data into the buffer until the buffer is full or the host transfer is complete. A command complete interrupt is generated at the end of the transfer.

A disk write task begins to store the host data to disk. Host write commands continue to be accepted and data transferred to the buffer until either the write command stack is full or the data buffer is full. The drive may reorder write commands to optimize drive throughput.

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Contents HA RD Drive Produc T MA Nual DiamondMax Before You Begin U T I O NContents Product Specifications Handling and InstallationAT Interface Description Host Software InterfaceGlossary Interface CommandsService and Support Figures Manual Organization IntroductionMaxtor Corporation AbbreviationsKey Words Signal ConventionsConventions NumberingDiamondMax 6800 Key Features Product DescriptionProduct Features Functional / InterfaceDefect Management Zone DMZ On-the-Fly Hardware Error Correction Code ECCLogical Block Addressing Software ECC CorrectionBuffer Segmentation Read-Ahead ModeCache Management Automatic Write Reallocation AWRMajor HDA Components Cylinder Limitation Subsystem ConfigurationJumper Location/Configuration Dual Drive SupportPerformance Specifications Product SpecificationsDrive Configuration Models and CapacitiesPhysical Dimensions Parameter Standard MetricEPA Energy Star Compliance Power RequirementsPower Mode Definitions Environmental LimitsReliability Specifications Shock and VibrationCanadian Emissions Statement Safety Regulatory ComplianceRadiated Electromagnetic Field Emissions EMC Compliance Pre-formatted Drive Handling and InstallationHard Drive Handling Precautions Important NoticeUnpacking and Inspection Multi-pack Shipping ContainerRepacking Physical InstallationRecommended Mounting Configuration System Requirements Handling PrecautionsTools for Installation Drive Identification InformationGeneral Requirements Hard Drive IdentificationInstalling in a Device Bay Systems Using Cable SelectInstalling 5.25-inch Mounting Brackets and Rails Mounting Drive in SystemAttaching Interface and Power Cables Attaching System CablesBios Cmos Parameters System SetupSetting the Bios Cmos Hard Drive Preparation System Hangs During Boot Pin Description Summary Interface ConnectorAT Interface Description PIN Name Signal Name Signal Description Pin Description TableTiming Parameters Mode PIO TimingDMA Timing Mode MIN MAX Ultra DMA TimingSustained Ultra DMA Data In Burst Device Terminating an Ultra DMA Data In Burst Initiating an Ultra DMA Data Out Burst Device Pausing an Ultra DMA Data Out Burst Device Terminating an Ultra DMA Data Out Burst Host Software Interface Error RegisterFeatures Register Task File RegistersCylinder Number Registers Sector Count RegisterSector Number Register Device/Head RegisterCommand Register Command Name Command Code Parameters Used SDH SummaryDevice Control Register Control Diagnostic RegistersAlternate Status Register Digital Input RegisterInterrupt Handling Reset and Interrupt HandlingReset Handling Interface Commands Set Feature CommandsRead Verify Sectors Read CommandsRead Sectors Read DMA Read MultipleWrite Sectors Write CommandsSet Multiple Mode Write Verify SectorsWrite Multiple Write DMASet Feature Commands Set Features ModePower Mode Commands Sleep Mode Initialization Commands Identify Drive15-8 = PIO data transfer mode = Write Cache enabled Initialize Drive Parameters Format Track Seek, Format and Diagnostic CommandsExecute Drive Diagnostic A.R.T. Command Set Execute S.M.A.R.TNo Quibble Service Service and SupportService Policy SupportInternet MaxFax ServiceCustomer Service Access Time GlossaryCylinder Zero Gigabyte GB Logical Block Addressing Read Gate Signal THIN-FILM Media