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LOAD UNLOAD Command (1Bh) SDLT 600 SCSI Interface Guide

4-28 January 2005 81-81200-02 REV A01

4.5 LOAD UNLOAD Command (1Bh)

The LOAD UNLOAD command instructs the SDLT tape drive to load or unload the tape inside the

data cartridge. If no data cartridge is in the drive, the LOAD UNLOAD command returns a CHECK

CONDITION status with the Sense Key set to NOT READY. Likewise, if the drive receives a LOAD

UNLOAD command with the Immediate bit set and then it receives another command that requires

tape motion or if it receives a TEST UNIT READY command, the drive returns a CHECK

CONDITION status with the Sense Key set to NOT READY.

Before executing the LOAD UNLOAD command, the drive writes any cached write data to the tape.

Figure 4-12. LOAD UNLOAD Command Descriptor Block — Data Format

Bit

Byte

7 6 5 4 3 2 1 0

0 Operation Code (1Bh)

1 Reserved Immed

2 – 3 Reserved

4 Reserved Hold EOT ReTen Load

5 Control

Table 4-16. LOAD UNLOAD Command Descriptor Block — Field Descriptions

Field Name Description

Immed Immediate. When set to 1, the drive returns status as soon as the operation starts.

When set to 0, the drive returns status after the operation has completed.

Hold When set to 1, indicates that Enhanced Medium Auxiliary Memory (EMAM) is

accessible upon completion of the command but the medium is not repositioned

for access. When the Hold bit is set to 0 and the Load bit is set to 1, the medium

is positioned for access. When both the Hold and Load bits are set to 0, EMAM

is not accessible upon completion of the command.

EOT End of Tape. The drive ignores this bit unless both the EOT and Load bits are set

to 1, then the drive returns CHECK CONDITION status with Sense Key set to

ILLEGAL REQUEST.

ReTen Retension. Ignored. Retension operations are not needed.

SDLT 600

SCSI Interface Guide

SCSI Commands

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