Read (10) (28H); Figure 122. Read - IBM IC35L036UWDY10 - Ultrastar 36.7 GB Hard Drive Specifications

8.16 READ (10) (28h)

Byte
7 6
0
1 Reserved = 0
2 (MSB)
|
5
6
(MSB)
7
8
9 VU = 0

Figure 122. READ (10)

The READ (10) command requests the drive to transfer data to the initiator. The larger Logical Block
Address and Transfer Length fields permit greater quantities of data to be requested per command than
with the READ (6) command and are required to access the full LBA range of the larger capacity drives.
! Transfer length The number of contiguous blocks to be transferred. If the transfer length is zero, the
seek occurs, but no data is transferred. This condition is not considered an error. If read ahead is
enabled, a read ahead is started after the seek completes.
! DPO A DPO (Disable Page Out) bit of one indicates that the data accessed by this command is to be
assigned the lowest priority for being written into or retained by the cache. A DPO bit of one overrides
any retention priority specified in the MODE SELECT Page 8 Caching Parameters. A DPO bit of zero
indicates the priority is determined by the retention priority. The initiator should set the DPO bit when
the blocks read by this command are not likely to be read again in the near future.
! FUA Force Unit Access. A FUA bit of one indicates that the data is read from the media and not from
the cache. A FUA bit of zero allows the data to be read from either the media or the cache.
! RelAdr Relative Block Address is not supported. Must be set to zero.
Bit
5 4 3
Command Code = 28h
DPO FUA
Logical Block Address
Reserved = 0
Transfer Length
Reserved = 0
Ultrastar 146Z10 hard disk drive specifications
128
2 1 0
RelAdr
Reserved = 0
= 0
(LSB)
(LSB)
FLAG LINK