Seagate STT8000A manual Read command

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Chapter 5ATAPI Interface

Read command

Bit	7	6	5	4		3	2	1	0
Byte

0				Operation code (08h)

1				Reserved					1 (Fixed)

2	(MSB)

3				Transfer Length

4									(LSB)

5				Reserved

The Transfer Length specifies the number of fixed 512 byte blocks to be transferred. A transfer length of 0 indicates that no data is to be transferred but will initiate a read-ahead.

The DSC bit is reset (0) after this command is accepted and is set (1) when at least 52 blocks in the buffer are available for the next READ command. Issuing a READ command when the DSC bit is reset (0) will keep the ATA bus busy (BSY = 1) while the drive is reading the required data into the buffer. This delay could be more than a minute if exhaustive retries are required to read the data.

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STT8000A Product Manual

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Contents STT8000A Atapi Minicartridge Drive Product Manual Page FCC Notice Important Information About This Manual Table of Contents Atapi interface Tape format Glossary Acronyms and measurements Introduction Drive overviewSTT8000A internal drive without mounting brackets Features Typical system configurations Minicartridge technology overviewFlash Eeprom SoftwareReferences About this manual Chapter Title DescriptionSpecifications Physical specificationsOverview STT8000A 3.5-Inch mount general dimensions Power specifications Specification MeasurementPerformance specifications Feature SpecificationSpecification Operational Non-operational Environmental requirementsReliability Mean-Time-Between FailuresMean-Time-To-Repair Recommended tapes Tape capacities and formatsRegulatory compliance TUV & IEC-RHEINLANDInstallation IntroductionBefore you begin Handling guidelinesSetting jumpers Jumper block and jumper settingsInstalling the drive Aligning the drive in the computerMounting dimensions Mounting holes on internal drive without mounting brackets ATA-2 Interface pin assignments Pin Assignment Description SourceREQ Chapter Installation Drive operation and maintenance Front panel LEDUsing Travan cartridges Loading and unloading cartridgesSetting the write-protect switch Travan cartridge write-protect switch-locked positionLoading revised firmware via Seagate firmware cartridge Care and maintenance of the drive and cartridges Caring for tape cartridgesCaring for the drive Capstan Tape Head Troubleshooting Chapter ATA-2 Signals Atapi interfaceATA-2 Interface ATA registers AbrtBits Mnemonic Description Supported ATA Commands Previous Cmd Int ReasonFeature Number Set Feature Commands Atapi Identify Device A1h Atapi Packet Command A0h Atapi interface DSCErase command Inquiry command Bit ByteLoad/Unload command Locate command Log Select command Log Sense command Error Counter Page Read Following table presents the Error Counter Page layoutTape Capacity Page Code Following table presents the Tape Capacity Page layoutMode Select command Mode Sense command Code Description Mode Parameter Header Mode Block DescriptorMode Medium Partition Mode Capabilities and Mechanical StatusMode Tape Parameters Read command Read Position command Following table describes the Read Position layoutChapter Atapi Interface Request Sense command Following table describes the Request Sense layout Rewind command Space command Test Unit Ready command Write command Write Filemark command Write Buffer download microcode command Tape format Tape partitioningTrack positions Track numbering Track formatFrames General track layout Tape reference servo pattern BlocksWrite equalization RandomizationChapter Tape format Block diagram Theory of operationsCapstan drive motor assembly MechanicsCartridge load mechanism ChassisSensors and switches Control circuitsHead design Media-Travan minicartridges Travan minicartridgeGlossary Appendix a Glossary Glossary Appendix a Glossary Acronyms and measurements Acronyms and abbreviationsLSI Units of measurement Measure MeaningAppendix B Acronyms and Measurements