Pre-Fetch (34H); Figure 120. Pre-Fetch - IBM IC35L036UWDY10 - Ultrastar 36.7 GB Hard Drive Specifications

8.14 PRE-FETCH (34h)

Byte
7 6
0
1 Reserved = 0
2 (MSB)
3
4
5
6
7 (MSB)
8
9 VU = 0

Figure 120. Pre-Fetch

The PRE-FETCH command requests the drive to transfer data to the cache. No data is transferred to the
initiator.
! Transfer length 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 here are no more blocks 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.
! RelAdr (Relative Block Address) is not supported and must be set to zero.
Bit
5 4 3
Command Code = 34h
Reserved = 0
Logical Block Address
Reserved = 0
Transfer Length
Reserved = 0
Ultrastar 146Z10 hard disk drive specifications
126
2 1 0
Immed RelAdr
= 0 = 0
(LSB)
(LSB)
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