Maxtor Atlas 10K V, Руководство по эксплуатации продукта

Страница: 65 / 253

Maxtor Atlas 10K V
5-7
5.3 Status/Error Reporting
SCSI message-level errors are communicated by messages that are defined specifically
for that purpose. SCSI command-level errors are communicated by a status 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 TASK SET message
• ABORT TASK message
• TARGET RESET message
• CLEAR QUEUE message
• Unexpected disconnect
The status code is contained in bits 1 through 5 of the status byte. Bits 0, 6, and 7 are
reserved. Table 5-6 describes the status codes returned by the drive.
Table 5-6
Status Codes
5.4 Linked Commands
An I/O Process (task) may contain multiple commands that are linked together. The
initiator communicates this condition of linked (or unlinked) commands by setting (or
clearing) the Link bit of the Command Descriptor Block’s control word. A linked
Status Definition Meaning
00h GOOD The drive successfully completed the command.
02h CHECK CONDITION An Auto Contingent Allegiance (ACA) condition occurred.
08h BUSY
The drive cannot service the command at the moment, and its Com-
mand Descriptor Block has been discarded. The initiator can retry the
command at a later time. This status is returned when:
• A non-tagged command is received and the logical unit's com-
mand queue is full (all internal command buffers are in use).
• A disconnect privilege was not granted in the IDENTIFY mes-
sage of a queue-tagged I/O process (Parallel SCSI).
• A disconnect privilege was not granted in the IDENTIFY mes-
sage of a non-tagged I/O process and a command from another
initiator is currently active (Parallel SCSI)
• A command is received while an auto-contingent allegiance
condition exists for another initiator.
10h INTERMEDIATE
This status is returned for every command (except the last) in a series
of linked commands that was successfully completed. However, if the
command is terminated with other that GOOD status (such as
CHECK CONDITION, RESERVATION CONFLICT, OR
BUSY), the INTERMEDIATE status is not returned and the series of
linked commands and the task is ended.
18h RESERVATION CONFLICT
Another initiator has reserved the drive. (This status is never returned
for INQUIRY or REQUEST SENSE commands.)
28h TASK SET FULL
The drive cannot service the command at the moment, and its Com-
mand Descriptor Block has been discarded. (Returned for a tagged
command when all of the drive's internal command buffers are in use,
or when a host sends a tagged command while an Auto Contingent
Allegiance condition is pending for that initiator)