READ CAPACITY (CD-ROM mode)25h

READ capacity transfers Read Capacity data to the host.

Pre-execution checks:

Illegal Field

Fixed Bit

Flag Link

Bad LUN

Reservation

Deferred Error

Unit Attention

 

If the drive is not in CD-ROM mode, the request will return CHECK CONDITION status with a sense key Illegal Command.

Command descriptor block:

 

 

7

 

6

5

 

4

 

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

 

Operation

Code (25h)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

Logical Unit Number

 

 

 

 

Reserved (0)

 

RelAdr(0)

 

 

 

 

 

 

 

 

 

 

 

 

 

2

(MSB)

 

Logical Block Address (0)

 

 

 

 

 

 

 

 

 

 

 

 

 

5

 

 

 

 

 

 

(LSB)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

 

 

 

 

Reserved (0)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7

 

 

 

 

 

Reserved (0)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

8

 

 

 

 

Reserved (0)

 

 

 

PMI

 

 

 

 

 

 

 

 

 

 

 

 

 

9

 

 

 

 

 

Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

CDB fields:

Logical Block Address This flag is ignored. It is recommended that it should be zero.

PMI

This flag is ignored. It is recommended that it should be zero.

 

 

Read Capacity data

The following data is always returned:

 

7

 

 

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

0

(MSB)

 

 

 

Returned Logical Block Address

 

 

 

3

 

 

 

 

 

(0004B000h)

 

 

(LSB)

 

 

 

 

 

 

 

 

 

4

(MSB)

 

 

 

Block Length in bytes

 

 

 

7

 

 

 

 

 

(00000800h)

 

 

(LSB)

 

 

 

 

 

 

 

 

 

 

 

124 Commands