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Messages, Message out support, 2 messages – HP Q153090901 User Manual

Page 23: Chapter 2

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2 Messages

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.