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SCSI Description

Quantum Atlas 10K II Ultra160/m SCSI Hard Disk Drives 5–219

5.48 WRITE AND VERIFY Command (2Eh)

The WRITE AND VERIFY command writes host-supplied data to the unit and

verifies it was written correctly.

Bit

Byte

7 6 5 4 3 2 1 0

0 Operation Code (2Eh)

1 Reserved DPO Reserved BytChk RelAdr

2 - 5 Logical Block Address

6 Reserved

7 - 8 Transfer Length

9 Control

Figure 5–108 WRITE AND VERIFY Command Descriptor Block — Data Format

Table 5–102 WRITE AND VERIFY Command — Field Descriptions

Field Description

DPO Disable Page Out. When the value of the field is 1, the drive tells the

controller to bypass cache as much as possible. The buffers used for the

WRITE data are given a low priority. This bit may be useful if the host CPU is

performing a background copy operation and does not want to wipe out

the drive's cache.

When DPO is 0, the drive tells the controller to cache this WRITE data in a

normal manner.

NOTE: The drive normally assigns a low priority to write caching. Therefore,

the DPO bit in a WRITE command is essentially ignored.

BytChk Byte Check. When 1, the drive performs a byte-by-byte comparison of the

data written on the media with the data transferred from the initiator.

When 0, the drive performs a medium verification with no data

comparison of the sectors written by the command.

RelAdr Relative Address. This feature is not supported and the field must be 0.

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Quantum 10K II Bedienungsanleitung Seite 286