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SCSI Commands

Quantum DLT 8000 Tape System 5-7

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 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.

Table 5–4 Status Codes

Status

Code Definition Meaning

00h GOOD The drive successfully completed the command.

02h CHECK CONDITION A Contingent Allegiance condition occurred.

08h BUSY 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.

10h INTERMEDIATE GOOD 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.

18h RESERVATIONCONFLICT 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).

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