Chapter 3: Scsi Description; Scsi Overview - Quantum DLT 8000 Product Manual

This chapter provides a detailed description of the logical interfaces of the tape drive.
The drive is fully compliant with the ANSI SCSI-2 standard for tape drive devices and
implements many optional features
3.1

SCSI Overview

The Small Computer System Interface (SCSI) is a specification for a peripheral bus and
command set that is an ANSI standard. The standard defines an I/O bus that supports
up to 16 devices (wide SCSI).
ANSI defines three primary objectives of SCSI-2:
1. To provide host computers with device-independence within a class of
devices
2. To be backward compatible with SCSI-1 devices that support bus parity and
that meet conformance level 2 of SCSI-1
3. To move device-dependent intelligence to the SCSI-2 devices
Important features of SCSI-2 implementation include the following:
Efficient peer-to-peer I/O bus with up to 16 devices
Asynchronous transfer rates that depend only on device implementation and
cable length
Logical addressing for all data blocks (rather than physical addressing)
Multiple initiators and multiple targets
Distributed arbitration (bus contention logic)
Command queuing
Command set enhancement
Quantum DLT 8000 Tape System
Chapter 3
SCSI DESCRIPTION
3-1