Quantum DLT 2000 Handbook page 156

SCSI Interface
SCSI (Small Computer System Interface) is at the heart of DLTtape
drive control and communication. The SCSI interface is designed
to be an industry standard for device control and communication.
Among the SCSI commands supported by DLTtape firmware are
ERASE, LOAD-UNLOAD, LOCATE, WRITE, READ, READ
POSITION, and REWIND. Supported SCSI messages, which are
used to manage the physical path between the host and the
DLTtape drive, include ABORT, BUS DEVICE RESET, CLEAR
QUEUE, DISCONNECT, WIDE DATA TRANSFER REQUEST,
and many others.
Like many "standards," SCSI is interpreted by each system vendor
in their own unique way. Often, these differences among versions
of SCSI are subtle, yet they are significant enough to adversely
effect drive operation if not recognized.
One of the biggest jobs performed by DLTtape system firmware is
implementation of the SCSI protocol, including commands, mes-
sages, and options. Firmware customization is the primary means
used to ensure that end users, no matter which host system they
may be using, enjoy all of the benefits offered by DLTtape technol-
ogy. Identifying and resolving differences among vendor imple-
mentations of SCSI occurs during Vendor Qualification.
Firmware Speeds Vendor Qualification
Although all DLTtape drives are manufactured by Quantum
Corporation (or under license by Tandberg Data), the vast majority
of DLTtape drives are resold by system OEMs such as Compaq, Dell,
HP, IBM, and Sun, as well as tape library manufacturers. These dri-
ves are typically sold as part of complete computer systems or incor-
porated into tape library systems.
QUANTUM DLTtape HANDBOOK 15.3