ACL 4/52 Software Interface Guide
Document 6211225-03
Version 3.0
Chapter Overview
3-3
Chapter Overview
This chapter describes the specific terminology of the Small Computer
Systems Interface (SCSI-2) in relation to the ACL 4/52.
SCSI Interface
Note
SCSI-2 terminology is listed below with its ACL 4/52 equivalent:
•
Logical Unit is the Library.
•
Initiator is the Host Computer.
•
Data Transfer Element is the Tape Drive.
•
Medium Transport Element is the Gripper Mechanism.
•
Storage Element is a Bin in the Fixed Storage Array.
•
Import Export Element is a Bin in the Load Port.
The ACL 4/52 is a SCSI-2 medium change device. The host computer
serves as the SCSI initiator and issues commands to the library and
tape drives which act as SCSI targets.
The library provides only SCSI target support. It does not perform any
of the initiator functions. The library has its own SCSI address separate
from any other SCSI devices including the tape drives.
The library does not support SCSI queuing or linked commands. All
element addresses must be specified absolutely; no relative addressing
is permitted.
The amount of data transferred between the host and the library is
minimal. For this reason, the library does not support either
synchronous or wide data transfers.
The library is intended for use with SCSI-2 initiators. It cannot be used
with a SCSI-I initiator.
The library does not support the Change Definition Command,
Asynchronous Event Notification or extended contingent allegiance.
Note
The message and command sections of this chapter assume that you
have significant knowledge of the SCSI Specification.