Quantum 1200 Series DAT Autochanger Betriebsanweisung PDF herunterladen (Seite 34)

Supported SCSI Messages SDLT 600 SCSI Interface Guide

3-6 January 2005 81-81200-02 REV A01

3.2.5 IDENTIFY (80h - FFh)

Either the initiator or the SDLT tape drive sends the IDENTIFY message to establish or re-establish

the physical connection path between an initiator and drive for a particular logical unit under the

conditions listed below. Figure 3-2 shows the format of the IDENTIFY message and Table 3-5

describes the data field contents.

Figure 3-2. IDENTIFY Message — Data Format

COMMAND The drive discards the DISCONNECT message and enters the BUS FREE

phase. The drive ignores the ATTENTION request while it fetches the

Command Descriptor Block. The drive does not switch to MESSAGE OUT

until the current DMA completes.

DATA The drive ignores the ATTENTION request while the current data transfer

completes; that is, the drive does not switch to MESSAGE OUT until after

the current DMA completes. The drive returns a MESSAGE REJECT

message and responds with CHECK CONDITION status, indicating the

command aborted because of an invalid message.

STATUS The drive sends a MESSAGE REJECT message, then sends TASK

COMPLETE.

MESSAGE IN The drive sends a MESSAGE REJECT message and enters the BUS FREE

phase.

Bit 7 6 5 4 3 2 1 0

Identify DiscPriv LUN

Table 3-5. IDENTIFY Message — Field Descriptions

Field Description

Identify Must be set to 1, indicating that the current message is an IDENTIFY message.

DiscPriv Disconnect Privilege. May be set to 0 provided that no other I/O process is

currently active in the drive. If this bit is not set to 1 and other I/O processes are

currently active in the drive, the drive returns a BUSY status.

LUN Logical Unit Number.

Table 3-4. Drive’s Response to DISCONNECT Message (Continued)

BUS Phase Drive Response

1 2 ... 29 30 31 32 33 34 35 36 37 38 39 ... 293 294

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