Status/Error Reporting - Quantum DLT 8000 Product Manual

5.1.3 Status/Error Reporting

SCSI message-level errors are communicated by messages that are defined specifically
for that purpose (for example, MESSAGE PARITY ERROR, MESSAGE REJECT).
Message-level errors are also handled by drive-managed retries. Refer back to Chapter
4 for more detailed message-handling information.
SCSI command-level errors are communicated by a status code that is returned by the
drive during the STATUS phase. This phase occurs at the end of each command,
unless the command is terminated by one of the following events:
•
ABORT message
•
BUS DEVICE RESET message
•
Hard reset condition
•
Unexpected disconnect
The status code is contained in bits 1 through 5 of the status byte. Bits 0, 6, and 7 are
reserved. Table 5–4 describes the status codes returned by the drive.
Status
Code Definition
00h GOOD
02h CHECK CONDITION
08h BUSY
10h INTERMEDIATE GOOD
18h RESERVATIONCONFLICT
Table 5–4 Status Codes
Meaning
The drive successfully completed the command.
A Contingent Allegiance condition occurred.
The drive cannot service the command at the
moment, and its Command Descriptor Block has
been discarded. The initiator can retry the
command at a later time.
This status is returned instead of a GOOD status
for commands issued with the LINK bit set.
Following the return of this status, the drive
proceeds to the COMMAND phase for the transfer
of the next linked command.
Another initiator has reserved the drive when it
has been reserved for another initiator with a
RESERVE UNIT command (this status is never
returned for INQUIRY or REQUEST SENSE
commands).
Quantum DLT 8000 Tape System
SCSI Commands
5-7