scope:

The SCSI family of standards provides for many different types of SCSI devices (e.g., disks, tapes, printers, scanners). This standard defines a device model that is applicable to all SCSI devices. Other SCSI command standards (see 3.1.18) expand on the general SCSI device model in ways appropriate to specific types of SCSI devices. The set of SCSI standards specifies the interfaces, functions, and operations necessary to ensure interoperability between conforming SCSI implementations. This standard is a functional description. Conforming implementations may employ any design technique that does not violate interoperability. This standard defines the SCSI commands that are mandatory and optional for all SCSI devices. Support for any feature defined in this standard is optional unless otherwise stated. This standard also defines the SCSI commands that may apply to any device model.