Chapter 5 SCSI Interface
SCSI Message System
54
Quantum|ATL PowerStor L200 Series Library User’s Guide
Other SCSI
Functionality
5
Linked commands and untagged queuing are supported.
Bus Phases
5
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.
Attention Signal
Response
5
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
.
SCSI Message System
5
This section discusses status phases, messages, and bus parity
errors.
Status Phase
5
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
).
Summary of Contents for PowerStor L200
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Page 7: ...Contents Quantum ATL PowerStor L200 Series Library User s Guide vii Glossary 87 Index 93...
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