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DLT2000 SCSI Interface
DLT2000/DLT2700 Cartridge Tape Subsystem 8-121
Count
When spacing over blocks or marks, the Count field is interpreted as follows:
•
A positive value N causes forward movement over N blocks or marks. The tape is
logically positioned after the Nth block or mark on the EOM/P side.
•
A zero value causes no change in the logical position.
•
A negative value -N (two's complement notation) causes reverse movement over N
blocks or marks. The tape is logically positioned on the BOM/P side of the Nth
block or mark.
•
When spacing to EOD, the Count field is ignored. Forward movement occurs until
the drive encounters EOD. The position is such that a subsequent WRITE
command would append data after the last object that has been written to tape
before EOD.
When executing SPACE, the drive implements the following hierarchy:
Blocks - lowest
Filemarks
EOD
BOM/P or EOM/P - highest
Therefore, SPACE N blocks will halt with GOOD status after the Nth block, or with
CHECK CONDITION status on any occurrence of Filemark, EOD, BOM/P, or
EOM/P. A space N Filemarks will halt on the Nth Filemark or on any occurrence of
EOD, BOM/P, or EOM/P, and so on.
Depending on the size of blocks, read ahead data in the buffer allows some spacing
requests to be satisfied without tape movement.
Summary of Contents for DLT 2500
Page 18: ...Table of Contents xviii DLT2000 DLT2500 DLT2700 Cartridge Tape Subsystem ...
Page 20: ...Revision History xx DLT2000 DLT2500 DLT2700 Cartridge Tape Subsystem ...
Page 146: ...Firmware Update From Tape 7 18 DLT2000 DLT2500 DLT2700 Cartridge Tape Subsystem ...
Page 291: ...DLT2000 SCSI Interface DLT2000 DLT2700 Cartridge Tape Subsystem 8 145 ...
Page 327: ...Sense Key Information C 6 DLT2000 DLT2500 DLT2700 Cartridge Tape Subsystem ...
Page 345: ...Index 8 DLT2000 DLT2500 DLT2700 Cartridge Tape Subsystem ...