HP Q153090901 - Manual (Page 124)

Commands 124
READ CAPACITY
(CD-ROM mode)
25h
R EAD capacity transfers Read Capacity data to the host.
Pre-execution checks:
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:
CDB fields:
Read Capacity data
The following data is always returned:
Illegal Field Fixed Bit Flag Link Bad LUN
Reservation Deferred Error Unit Attention
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
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.
7 6 5 4 3 2 1 0
0 (MSB) Returned Logical Block Address
(0004B000h)
3 (LSB)
4 (MSB) Block Length in bytes
(00000800h)
7 (LSB)