ACL 4/52 Software Interface Guide
Document 6211225-03
Version 3.0
D-8
Exabyte Emulation Design Philosophy
Exabyte Emulation Design Philosophy
The Exabyte Emulation is designed to accept as many commands as possible
from a host designed to operate an Exabyte EXB-120 library. Where the
operations of an ACL 4/52 is a superset of Exabyte EXB-120 behavior, the
extended behavior is retained. Where Exabyte EXB-120 behavior can not
actually be performed by an ACL 4/52, efforts are made to responsibly mimic
the interface interactions.
There are physical differences between the libraries that preclude some
Exabyte EXB-120 commands from operating on an ACL 4/52. Most of these
commands, such as Receive Diagnostics, use a fixed response to mimic a
successful call. The Write Firmware command should not act successful if not
executed, so a Check Condition is returned.
There are capabilities of the ACL 4/52 library that allow it to perform actions
that an EXB-120 can not. This includes a move to the Transport Element, a
move with the same source and target, or a third party reservation. Though an
Exabyte EXB-120 would reject these commands, the ACL 4/52 in Exabyte
Emulation Mode will accept any commands that would operate in Standard
Interface Mode. This super-set behavior will not cause problems for an
Exabyte host as it only affects commands that would be an error to an Exabyte
EXB-120.
