Table of Contents
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Chapter 5 SCSI Interface
SCSI Message System
Other SCSI
5
Functionality
5
Bus Phases
Attention Signal
5
Response
SCSI Message System
5
Status Phase
54
Linked commands and untagged queuing are supported.
The library conforms to the bus state transition table shown in the
SCSI-2 Standard, Phase Sequences. The information in the following
sections also applies.
The library responds to an attention (ATN) condition at every
phase transition, as long as the initiator sets the ATN bit before the
target deasserts the request (REQ) for the last byte of the previous
phase. Generally, ATN is recognized immediately by the library,
and it changes the bus phase to Message Out.
This section discusses status phases, messages, and bus parity
errors.
The library enters the status phase just once per command, unless
the initiator requests a retry. The only exception is during error
cases when the device goes immediately to BUS FREE, as defined
in the SCSI-2 standard. The library can return a variety of status
bytes (see
table
12).
Quantum|ATL PowerStor L200 Series Library User's Guide
5
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