Quantum DLTtape DLT 7000, Product Manual

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Quantum DLT 7000 Tape System 3-1
Chapter 3
SCSI DESCRIPTION
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 set enhancement