Messages
23
2Messages
This chapter includes all SCSI messages, both supported and unsupported. Parts of this chapter
come from Section 5, Logical Characteristics, of the SCSI standards (see page 11).
The message system provides an initiator and a target on the SCSI bus with a means of managing
communication. The available messages are listed in this chapter.
Message Out support
Name Code Support
Abort 06h An abort condition is generated (see “Abort handling” on page 14).
Bus Device Reset 0Ch A reset condition is generated (see “Reset strategy” on page 13).
Extended Message 01h See “Extended Message Support” below.
Identify 80h+ The Identify Out message is sent by the initiator to identify the Logical
Unit to be accessed and to set Disconnect Privilege.
Initiator Detected
Error
05h The initiator has detected an error in the data being sent in a Command,
Data or Status phase. The drive will send a restore data pointers
message to retry the data transfer. (See “Message In support” below for
details).
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. (See “Message In support” below for details).
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 Reject 07h This message is sent when the initiator does not support a message sent
by the drive or that the message is 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, 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.
No Operation 08h This message has no effect and is ignored.
