SCSI Interface Overview
Page
6
Message Hex
Code
Definition
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
indicate 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.
Message
Reject
07h
This message is sent to the initiator when the message received by
the drive is unsupported or inappropriate.
Restore
Pointers
03h
This message causes the initiator to reset its data transfer pointers to
the values they held when the last Save Data Pointers message was
sent. It will be sent when a parity error is detected on the bus or
when an Initiator Detected Error message is received in order to retry
the data phase.
Save Data
Pointer
02h
This message instructs the initiator to save its current data transfer
pointer for use with a subsequent Restore pointers message. This
message will always be sent before a Disconnect message during
data phases.
2.3.5
Outbound messages
The following table lists host to drive SCSI messages and their definitions.
Message Hex
Code
Definition
Abort 06h
An abort condition is generated. See Message exception handling on
page 9.
Bus Device
Reset
0Ch
A reset condition is generated. See Message exception handling on
page 9.
Extended
Message
01h
See Extended messages on the following page for a description of
extended message support
Identify 80h+
The Identify Out message is sent by the initiator to identify the Logical
Unit to be accessed and to set Disconnect Privilege. The LUNTAR flag
must be zero.
The Identify Out message must be sent as the first thing after
selection. If it is sent at any other time, the drive will respond with a
message reject message and go to Bus Free.
Initiator
Detected
Error
05h
The initiator has detected an error in the data being sent in a Message
Command, Data or Status phase. The drive will retry the data burst or
message.
If the message is received immediately after an Identify message or
after the Command Complete message has been sent, the drive will go
Bus Free.
Message
Parity Error
09h
The initiator has detected a parity error in a message. The drive will
retry the message.
If the message is received during a Command, Data or Status phase,
immediately after an Identify message or after the Command Complete
message has been sent, the drive will go Bus Free.
Message
Reject
07h
This message is sent when the initiator does not support a message
sent by the drive or considers the message inappropriate. If the
message being rejected is Disconnect, Synchronous Data Transfer
Request or Wide Data Transfer Request, the operation continues
without those features. For all other messages except Restore
Pointers, the message is treated as an Abort message.
If the message is received during a Command, Data or Status phase,
immediately after an Identify message or after the command complete
message has been sent, the drive will go Bus Free.
Summary of Contents for LTO 4
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