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Chapter 5 SCSI Interface

SCSI Message System

54 Quantum|ATL PowerStor L200 Series Library User’s Guide

Other SCSI

Functionality

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

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

1 2 ... 65 66 67 68 69 70 71 72 73 74 75 ... 111 112

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Quantum L200 Guía de usuario Pagina 70