Read Extended (28) - IBM DDRS-39130 - Ultrastar 9.1 GB Hard Drive Specifications

7.17 READ EXTENDED (28)

Byte
7 6
0
1 LUN
2 (MSB)
3
4
5
6
7 (MSB)
8
9 VU = 0
Figure 96. Read Extended (28)
The READ EXTENDED command requests the file 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 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 Disable Page Out function is not supported, however, D P O bit set to 1 is not rejected and
ignored internally.
FUA Force Unit Access. A F U A bit of 1 indicates that the data is read from the media and not
from the cache. A F U A bit of 0 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.
126
O E M Spec. of DDRS-3xxxx
Bit
5 4 3
Command Code = 28h
DPO FUA
Logical Block Address
Reserved = 0
Transfer Length
Reserved = 0
2 1 0
Reserved RelAdr
= 0 = 0
(LSB)
(LSB)
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