Test Unit Ready

2.41Test Unit Ready (00h)

Operation Code is (00h).

The TEST UNIT READY command checks that a cartridge is loaded and that the drive is ready to operate. "Ready" has different meanings depending on whether the drive has accessed a logical unit by loading the disc tray:

Before access to logical unit : Magazine is inserted and the drive is ready to read.

After an access to logical unit: A disc is in the specified logical unit (or tray) and is ready to be accessed.

The TEST UNIT READY command does not load the logical unit's tray. (See REZERO UNIT) See 1.3 for Disc Status Information.

A Not Ready condition can occur when:

(1)No magazine is inserted in the drive.

(2)The magazine cannot be inserted or ejected.

(3)The drive cannot read TOC information on a disc.

(4)There is no disc present.

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