It is intended to show how the different SCSI standards are inter-related.
Only the externally observable behavior is defined in SCSI standards.
The SCSI standards define commands, protocols and electrical and optical interfaces.
In addition to many different hardware implementations, the SCSI standards also include an extensive set of command definitions.
In the published SCSI standards, commands are designated as "mandatory," "optional" or "vendor-unique."
Domain Validation is part of the SCSI standard.
The SCSI standard allows for two different threshold levels, noncritical (warning) and critical.
High performance/high capacity data storage: early workstations tended to use proprietary disk interfaces until the emergence of the SCSI standard in the mid-1980s.
(T10 is responsible for all SCSI standards.)
All SCSI standards have been modular, defining various capabilities which manufacturers can include or not.