HP Surestore 28/48-Slot with DLT7000 Digital Linear Tape SCSI-2 Drive and SCSI - Page 282

Modifying a SCSI Disk Driver for the Tape Drive, Change Considerations

Page 282 highlights

Table B-2 Programmer's Tips Modifying the SCSI Driver Modifying a SCSI Disk Driver for the Tape Drive Though a SCSI disk driver can be modified for the tape drive, this is an involved process since they are very different drivers. To modify a SCSI disk driver, refer to the Appendix A in the HP-UX Driver Development Guide for the Hewlett-Packard version (HP Part No. 98577-90001). Change Considerations Consider this list of possible changes/issues when modifying a disk driver for the tape drive. Abort Behavior: When a command is aborted while the tape drive is logically disconnected from the bus, it will not immediately respond. The abort will be ignored until the tape drive reconnects. At this point, the abort is recognized and the appropriate check condition status returned. Removable Media: Because the tape cartridge is removable, several unit attention conditions unique to digital linear tape drives can be generated: Unit Attention Conditions Sense Key Not Ready Unit Attention Unit Attention Medium Error Data Protect Hardware Error Sense Code No Disk Medium Changed Poweron or Reset Cannot Read Media Unknown Format Write Protected Load/Unload Failure Occurs Media is not loaded Each time the autochanger swaps a tape cartridge After poweron or reset for all SCSI devices. Medium Format Corrupted When tape is an unknown type and not compatible When tape is write protected Something mechanically impedes the load/unload process B- 12 Appendix B

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B-12
Appendix B
Programmer’s Tips
Modifying the SCSI Driver
Modifying a SCSI Disk Driver for the Tape Drive
Though a SCSI disk driver can be modified for the tape drive, this is an
involved process since they are very different drivers. To modify a SCSI
disk driver, refer to the Appendix A in the HP-UX Driver Development
Guide for the Hewlett-Packard version (HP Part No. 98577-90001).
Change Considerations
Consider this list of possible changes/issues when modifying a disk
driver for the tape drive.
Abort Behavior
: When a command is aborted while the tape drive is
logically disconnected from the bus, it will not immediately respond. The
abort will be ignored until the tape drive reconnects. At this point, the
abort is recognized and the appropriate check condition status returned.
Removable Media
: Because the tape cartridge is removable, several
unit attention conditions unique to digital linear tape drives can be
generated:
Table B-2
Unit Attention Conditions
Sense Key
Sense Code
Occurs
Not Ready
No Disk
Media is not loaded
Unit Attention
Medium Changed
Each time the
autochanger swaps a tape
cartridge
Unit Attention
Poweron or Reset
After poweron or reset for
all SCSI devices. Medium
Format Corrupted
Medium Error
Cannot Read
Media Unknown
Format
When tape is an unknown
type and not compatible
Data Protect
Write Protected
When tape is write
protected
Hardware Error
Load/Unload
Failure
Something mechanically
impedes the load/unload
process