Seagate STT8000A manual Write equalization, Randomization

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Tape format

Chapter 6

Write equalization

The drive uses the technique of write equalization. RLL encoding has a 4:1 ratio in the minimum and maximum spacing between flux transitions. Write equalization inserts short pulses in the write current to break up the long spacing intervals. These pulses are too short to be detected in the read process but result in significant improvement in read-back resolution.

On 900 Oersted media, write equalization provides the benefit of compatibility with Magneto-Resistive (MR) heads. MR heads are prone to saturation by low frequency flux with high energy content. Equalization redistributes this energy to higher frequencies and eliminates the problem.

Randomization

To reduce problems resulting from long strings of repetitive data with a bad peak shift or amplitude characteristics, a data randomizer algorithm is used on all bytes in the data and control area of each block. This randomizing takes place prior to the encoding of the data.

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 Drive overview IntroductionSTT8000A internal drive without mounting brackets Features Minicartridge technology overview Typical system configurationsFlash Eeprom SoftwareReferences Chapter Title Description About this manualSpecifications Physical specificationsOverview STT8000A 3.5-Inch mount general dimensions Specification Measurement Power specificationsFeature Specification Performance specificationsEnvironmental requirements Specification Operational Non-operationalReliability Mean-Time-Between FailuresMean-Time-To-Repair Tape capacities and formats Recommended tapesTUV & IEC-RHEINLAND Regulatory complianceHandling guidelines InstallationIntroduction Before you beginJumper block and jumper settings Setting jumpersAligning the drive in the computer Installing the driveMounting dimensions Mounting holes on internal drive without mounting brackets Pin Assignment Description Source ATA-2 Interface pin assignmentsREQ Chapter Installation Front panel LED Drive operation and maintenanceLoading and unloading cartridges Using Travan cartridgesTravan cartridge write-protect switch-locked position Setting the write-protect switchLoading 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 Abrt ATA registersBits Mnemonic Description Previous Cmd Int Reason Supported ATA CommandsFeature Number Set Feature Commands Atapi Identify Device A1h Atapi Packet Command A0h DSC Atapi interfaceErase command Bit Byte Inquiry commandLoad/Unload command Locate command Log Select command Log Sense command Following table presents the Error Counter Page layout Error Counter Page ReadFollowing table presents the Tape Capacity Page layout Tape Capacity Page CodeMode Select command Code Description Mode Sense commandMode Block Descriptor Mode Parameter HeaderMode Capabilities and Mechanical Status Mode Medium PartitionMode Tape Parameters Read command Following table describes the Read Position layout Read Position commandChapter 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 Blocks Tape reference servo patternRandomization Write equalizationChapter Tape format Theory of operations Block diagramChassis Capstan drive motor assemblyMechanics Cartridge load mechanismSensors and switches Control circuitsHead design Travan minicartridge Media-Travan minicartridgesGlossary Appendix a Glossary Glossary Appendix a Glossary Acronyms and abbreviations Acronyms and measurementsLSI Measure Meaning Units of measurementAppendix B Acronyms and Measurements