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Scsi iii standards overview – IBM HANDBOOK 260 User Manual

Page 118

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RS/6000 43P 7043 Models 150 and 260 Handbook

Currently, SCSI-III has a transfer rate of 40 MB/s and includes Fast-20
Narrow and Fast-20 Wide.

SCSI-III will be a major step forward in the development of disk subsystems.
It further enhances the SCSI-II interface in the following ways:

• Provides three new physical interface layers, SSA, FC and FireWire.

These new layers provide better performance, higher availability and more
expendability to SCSI.

• Divides SCSI into more than 15 standards, each dealing with a separate

part. Because SCSI had become a very large standard, the separation
makes the SCSI standard easier to maintain and better to work with. It
also allows parts of SCSI-III to be formalized much sooner.

4.2.3.1 Overview of SCSI-III Standards
The breakdown of the SCSI-III standards is shown in Figure 29 and is
described in Table 18.

.

Figure 29. SCSI III Standards Overview

Medium Changer

Commands

Graphics

Commands

Controller

Commands

Multimedia

Commands

Block

Commands

Stream

Commands

Parallel

Fibre Channel

IEEE 1394

Serial Storage

Architecture

Interlocked

Protocol

Fibre Channel

Protocol

Serial Bus

Protocol

Serial Storage

Protocol

Architecture

Model

Command

Primary

Set

Physical Interface

Layer

Protocol

Layer

Device Model

Layer

Command Set

Layer

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