Maxtor 6800 manual Read Commands, Read Sectors, Read Verify Sectors

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INTERFACE COMMANDS

Read Commands

Read Sector(s)

Reads from 1 to 256 sectors, as specified in the Command Block, beginning at the specified sector. (A sector count of 0 requests 256 sectors.) Immediately after the Command register is written, the drive sets the BSY bit and begins execution of the command. If the drive is not already on the desired track, an implied seek is performed.

Once at the desired track, the drive searches for the data address mark of the requested sector. The data address mark must be recognized within a specified number of bytes, or the Data Address Mark Not Found error will be reported. Assuming the data address mark is found:

1.The data field is read into the sector buffer.

2.Error bits are set (if an error was encountered).

3.The DRQ bit is set.

4.An interrupt is generated.

The DRQ bit is always set, regardless of the presence or absence of an error condition after the sector. Upon command completion, the Command Block registers contain the numbers of the cylinder, head and sector of the last sector read. Back-to-back sector read commands set DRQ and generate an interrupt when the sector buffer is filled at the completion of each sector. The drive is then ready for the data to be read by the host. DRQ is reset and BSY is set immediately when the host empties the sector buffer.

If an error occurs during Read Sector commands, the read terminates at the sector where the error occurred. The host may then read the Command Block to determine the nature of that error, and the sector where it happened. If the error type is a correctable or an non-correctable data error, the flawed data is loaded into the sector buffer.

A Read Long command sets the Long bit in the command code and returns the data and the ECC bytes in the data field of the specified sector. During a Read Long, the drive does not check the ECC bytes to determine if there has been a data error. The Read Long command is limited to single sector requests.

Read Verify Sector(s)

Identical to the Read Sector(s) command, except that:

1.DRQ is never set,

2.No data is transferred back to the host and

3.The long bit is not valid.

7 – 2

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Contents HA RD Drive Produc T MA Nual DiamondMax U T I O N Before You BeginContents Handling and Installation Product SpecificationsHost Software Interface AT Interface DescriptionService and Support Interface CommandsGlossary Figures Maxtor Corporation IntroductionManual Organization AbbreviationsConventions Signal ConventionsKey Words NumberingProduct Description DiamondMax 6800 Key FeaturesFunctional / Interface Product FeaturesLogical Block Addressing On-the-Fly Hardware Error Correction Code ECCDefect Management Zone DMZ Software ECC CorrectionCache Management Read-Ahead ModeBuffer Segmentation Automatic Write Reallocation AWRMajor HDA Components Jumper Location/Configuration Subsystem ConfigurationCylinder Limitation Dual Drive SupportDrive Configuration Product SpecificationsPerformance Specifications Models and CapacitiesParameter Standard Metric Physical DimensionsPower Mode Definitions Power RequirementsEPA Energy Star Compliance Environmental LimitsShock and Vibration Reliability SpecificationsRadiated Electromagnetic Field Emissions EMC Compliance Safety Regulatory ComplianceCanadian Emissions Statement Hard Drive Handling Precautions Handling and InstallationPre-formatted Drive Important NoticeMulti-pack Shipping Container Unpacking and InspectionRecommended Mounting Configuration Physical InstallationRepacking Tools for Installation Handling PrecautionsSystem Requirements Drive Identification InformationHard Drive Identification General RequirementsInstalling 5.25-inch Mounting Brackets and Rails Systems Using Cable SelectInstalling in a Device Bay Mounting Drive in SystemAttaching System Cables Attaching Interface and Power CablesSetting the Bios Cmos System SetupBios Cmos Parameters Hard Drive Preparation System Hangs During Boot AT Interface Description Interface ConnectorPin Description Summary Pin Description Table PIN Name Signal Name Signal DescriptionPIO Timing Timing Parameters ModeDMA Timing Ultra DMA Timing Mode MIN MAXSustained 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 Features Register Error RegisterHost Software Interface Task File RegistersSector Number Register Sector Count RegisterCylinder Number Registers Device/Head RegisterCommand Register Summary Command Name Command Code Parameters Used SDHAlternate Status Register Control Diagnostic RegistersDevice Control Register Digital Input RegisterReset Handling Reset and Interrupt HandlingInterrupt Handling Set Feature Commands Interface CommandsRead Sectors Read CommandsRead Verify Sectors Read Multiple Read DMASet Multiple Mode Write CommandsWrite Sectors Write Verify SectorsWrite DMA Write MultipleSet Features Mode Set Feature CommandsPower Mode Commands Sleep Mode Identify Drive Initialization Commands15-8 = PIO data transfer mode = Write Cache enabled Initialize Drive Parameters Execute Drive Diagnostic Seek, Format and Diagnostic CommandsFormat Track Execute S.M.A.R.T A.R.T. Command SetService Policy Service and SupportNo Quibble Service SupportCustomer Service MaxFax ServiceInternet Glossary Access TimeCylinder Zero Gigabyte GB Logical Block Addressing Read Gate Signal THIN-FILM Media