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10
LTO SCSI Interface Manual
SCSI Messages and Status Codes
SCSI Messages
The SCSI message codes, descriptions, and directions are given in the following
table. Each of these SCSI messages are supported by the Seagate LTO drive.
Code
Description
Direction
00h
Command Complete
In
01h
Extended Message*
In/Out
02h
Save Data Pointers
In
03h
Restore Pointers
In
04h
Disconnect
In
05h
Initiator Detected Error
Out
06h
Abort
Out
07h
Message Reject
In/Out
08h
No Operation
Out
09h
Message Parity Error
Out
0Ch
Bus Device Reset
Out
23h
Ignore Wide Residue
In
80h+
Identify
In/Out
In = Drive to host
Out = Host to drive
* Only two extended messages are Supported: Synchronous Data Transfer Request and Wide Data
Transfer Request.
Inbound messages
The following table lists drive to host SCSI messages and their definitions.
Message
Hex Code
Definition
Command
Complete
00h
This message is sent by the drive at the end of the status phase to
indicate that a command is complete. Once the message is sent, the
drive releases the bus and goes to Bus Free
Disconnect
04h
This message is sent by the drive to indicate that it is about to dis-
connect from the bus and go to Bus Free. During a Data phase, it is
always preceded by a Save Data Pointers message. If a Message
Reject message is received in response to this message, then the
disconnect is prevented.
Extended
Message
01h
See page 11 for a description of extended message support
Identify
80h+
An Identify in message is sent to the initiator during reconnect to in-
dicate which Logical Unit is reconnecting. The Disconnect Privilege
and LUNTAR flags will both be clear
Ignore Wide
Residue
23h
This message is sent by the drive to the initiator to indicate that a
byte on a wide bus is not valid. This will be supported whenever a
wide transfer is active.
