Hitachi Ultrastar 15K450 (FC-AL) Hard Disk Drive Specification
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19.14 PRE-FETCH (34)
Table 174:PRE-FETCH (34)
The PRE-FETCH command requests the drive to transfer data to the cache. No data is transferred to the Initiator.
•Transfer length field specifies the number of contiguous blocks of data that are to be transferred into the cache. A
transfer length of zero indicates that blocks are to be transferred into the cache until the segment is filled or until the
last block on the media.
•Immed (Immediate) must be zero. An immediate bit of zero indicates that the status shall not be returned until the
operation has completed.
If the Immed bit is set to one, the drive returns a Check Condition status. The sense key shall be set to Illegal
Request and the additional sense code shall be set to Invalid Field in CDB.
Byte Bit
76543210
0 Command Code = 34h
1 Reserved = 0 Reserved = 0 Immed
= 0 Obso-
lete
2-5
(MSB)
Logical Block Address
(LSB)
6 Reserved = 0
7-8 (MSB) Transfer Length
(LSB)
9 VU = 0 Reserved = 0 FLAG LINK