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SCSI Commands
5-12
Quantum DLT 8000 Tape System
5.1.7 Data Cache and Tape Write Interaction
The Quantum DLT 8000 system tape drive contains a data cache that buffers blocks
(records) until they are written to tape. This section describes when those blocks are
written, or “flushed” to tape. A Mode Select parameter allows the data cache to be
disabled (unbuffered mode). In this mode, every WRITE command causes data to be
written to the tape medium before the STATUS byte and the COMMAND COMPLETE
message are returned to the host.
NOTE
Unbuffered mode is NOT recommended due to the poor performance that may
result.
The contents of the write data cache are written to the tape medium under the following
circumstances:
•
When two or more WRITE FILEMARKS commands are issued without intervening
tape motion commands.
•
When a WRITE 0 FILEMARKS command is issued.
•
When data has been in the cache longer than the maximum time specified by the
value of the Mode Parameter “Write Delay Time” (the default is 20 seconds).
•
When a non-write type media access command is received (for example, SPACE,
READ, UNLOAD, LOCATE, ERASE).
Summary of Contents for DLTtape DLT 8000
Page 1: ...DLTTM 8000 Tape System Product Manual Nov 10 2003 81 60118 06...
Page 5: ...USER MANUAL STATEMENTS FOR CLASS B EQUIPMENT continued...
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Page 26: ...Table of Contents xxiv Quantum DLT 8000 Tape System...
Page 36: ...About This Manual Quantum DLT 8000 Tape System xxxii...
Page 54: ...General Description and Specifications 1 18 Quantum DLT 8000 Tape System...
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Page 376: ...Appendix A Definition of Vendor Unique Sense Data Information A 4 Quantum DLT 8000 Tape System...
Page 386: ...Appendix C Updating the Firmware C 6 Quantum DLT 8000 Tape System...
Page 396: ...Appendix E Visual Inspection Procedure for DLTtape Cartridges E 8 Quantum DLT 8000 Tape System...
Page 406: ...Appendix G DLT 7000 Emulation Feature G 8 Quantum DLT 8000 Tape System...
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