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C H A P T E R
General Information
This chapter describes the small computer system interface (SCSI) and the Fibre
Channel interface (FC) for the SL500 tape library. This manual does not describe
the Fibre Channel interface to the tape drives.
The SCSI Bus Interface
The libraries' SCSI interface conforms to SCSI specifications and is accepted by:
American National Standards Institute (ANSI X3.131)
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European Computer Manufacturing Association (ECMA-111)
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Federal Information Processing Standard (FIPS-131)
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International Standards Organization (ISO-9316)
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Overview
The small computer system interface operates locally as an input and output (I/O)
bus that uses a common command set to transfer controls and data to all devices.
The main purpose of this interface, called the SCSI bus, is to provide host computer
systems with connections to a variety of peripheral devices, including disk
subsystems, tape subsystems, printers, scanners, CD-ROMs, optical devices,
communication devices, and libraries.
The SCSI bus design for the library provides a peer-to-peer, I/O interface that
supports up to 16 devices and accommodates two hosts.
Peer-to-peer interface communication can be from:
Host to host
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Host to peripheral device
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Peripheral device to peripheral device
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SCSI terms defining communication between devices on the SCSI bus include:
Initiator is the device that requests an operation.
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Target is the device that performs the operation requested.
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Some targets are control units that can access one or more physical or virtual
peripheral devices addressable through the control unit. These peripheral devices
are called logical units and are assigned specific addresses or logical unit numbers
(LUNs).
96122 • Revision: F
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