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SCSI Description

3-24 Quantum DLT 8000 Tape System

• When switching the DATA BUS from in to out, the drive releases the DATA

BUS no later than a deskew delay after negating the I/O signal.

• The ATN and RST signals can change as defined under the descriptions for

the attention condition (Section 3.6.1) and reset condition (Section 3.6.2).

3.5.5.4 STATUS Phase

The tape drive enters the status phase just once per command unless a retry is requested

by the initiator. The only exception is during error cases when the device goes

immediately to bus free, as defined in the ANSI SCSI-2 specification.

Status bytes the tape drive can return are as follows:

Status Bytes Returned from Tape

Drive

Definition

GOOD (00h) This status indicates that the drive successfully

completed the command.

CHECK CONDITION (02h) A contingent allegiance condition occurred. The

REQUEST SENSE command should be sent following

this status to determine the nature of the event.

BUSY (08h) Target is busy. This status is returned whenever the

device is unable to accept a command from an

otherwise acceptable initiator. The initiator should

reissue the command at a later time.

INTERMEDIATE GOOD (10h) This status is returned instead of GOOD for commands

issued with the LINK bit set = 1. Following the return of

this status, the drive proceeds to the COMMAND phase

for the transfer of the next linked command.

RESERVATION CONFLICT (18h) This status is returned by the drive whenever a SCSI

device attempts to access the drive when it has been

reserved for another initiator with a RESERVE UNIT

command.

COMMAND TERMINATED (22h) This status is returned for a command that was

terminated via a TERMINATE I/O PROCESS message. This

status also indicates that a contingent allegiance

condition has occurred.

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Quantum DLT 8000 Handbuch Seite 126