ACL 4/52 Software Interface Guide
Document 6211225-03
Version 3.0
D-6
SCSI Command Differences
SCSI Command Differences
This section describes the operational differences of commands act in the
Exabyte Emulation Mode, compared to the Standard Host Interface described
in the other sections of this manual.
Inquiry (12h)
In Exabyte Emulation, the Inquiry command reports the Vendor ID field as
“EXABYTE
b
” and the Product ID field as “EXB-120
bbbbbbbbb,
” where “
b
” is
a blank character (20h). There is also a vender specific field, 20 bytes long
filled with NULLs (00h), following the standard inquiry data (bytes 36-55).
Move Medium (A5h)
In Exabyte Emulation mode, the Move Medium command supports the
vendor specific Entry/Exit Position field. The field is in bits 7-6 of byte 11 of
the Move Medium command. Normally this field is unused and set to 00b.
To command the ACL 4/52 Load Port both the source and target elements
must be set to an element in the Load Port (40h - 43h in the standard
configuration). The command will complete when the axis finishes the
commanded motion.
To command the Load Port to Open, place a 01b in the EEPos field. The door
will swing open automatically and completes when the door is locked open.
To command the Load Port to Close, place a 10b in the EEPos field. The door
can not close automatically, so an operator message is sent to the Control
Panel instructing the operator to close the Load Port. If the operator does not
close the door within 30 seconds, the library generates an IOD Timeout Error
(8 8C 01). The command completes when the door is locked closed and the
Load Port is inventoried (if the library is configured to Auto-Inventory), or
when the Load Port times out (if not closed after 30 seconds).
Unlike the Exabyte EXB-120 that is being emulated, the ACL 4/52 is capable
of operating when the Load Port is open. The ACL 4/52 will perform any
command it normally would, except of course a Move Medium to or from the
Load Port.
Read Element Status (B8h)
In Exabyte Emulation Mode the Read Element Status command’s Element
Descriptor returns 52 bytes, omitting the ACL 4/52 vender unique bytes
(bytes 52-53). Also, the Volume Identification field will only have valid data
in the first 8 bytes (as opposed to 10 valid bytes in an ACL 4/52) with the
remainder being blanks (20h).