100 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