scope:

This technical report provides guidance to experienced implementors and users of parallel SCSI beyond that contained in the formal standards. SCSI technology offers many different options and is used in a broad set of applications ranging from notebooks to data centers. It is often desirable to build on the established installed base but certain extensions may occasionally be needed to expand the capabilities for specific applications. Examples of such extensions include longer lengths, more devices, mixing different kinds of SCSI device interfaces within the same system, and dynamic physical reconfiguration of SCSI components. For the most part the present SCSI standards describe homogeneous implementations with conservative requirements on the components. This technical report describes how some of these extensions can be accomplished by placing specific constraints on application parameters for the sake of extending specific capabilities. Parameters include maximum data phase speed, path width, wire gauge of cables, propagation velocity of signals in cables, transmission line effects, supply voltages used, configurations, and transmission modes.

Major clauses describe the uses of and requirements for circuitry that can physically partition the SCSI bus into segments without any effect on the software or firmware required.

Material is also included on design and implementation issues that may not be obvious from the standards.