5.45WRITE (10) Command (2Ah)

The WRITE (10) command requests that the drive write initiator-supplied data to the medium. The data format and field descriptions are shown in Table 5-208and Table 5-209respectively.

Table 5-208WRITE (10) Command Descriptor Block-Data Format

Bit

7

6

5

4

 

3

2

 

1

0

Byte

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

Operation Code (2Ah)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

Reserved

 

DPO

 

FUA

 

Reserved

RelAdr

 

 

 

 

 

 

 

 

 

 

2 - 5

 

 

 

Logical Block Address

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

 

 

Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

7 - 8

 

 

 

Transfer Length

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9

 

 

 

Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 5-209WRITE (10) Command-Field Descriptions

 

 

Field

Description

 

 

 

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.

DPO

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

 

 

ner.

 

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

 

bit in a WRITE command is ignored.

 

Force Unit Access. When 1, the data must be written on the medium before GOOD status

FUA

is returned. When 0, GOOD status may be returned after the data is fetched from the ini-

tiator and before it is written to the medium. If the WCE (Write Cache Enable) bit on the

 

MODE SELECT command Caching Page is clear, the FUA bit is ignored and behaves as

 

if it were always set (that is, if WCE = 0, the controller forces FUA = 1).

Logical Block

The address of the first logical block where the Write operation will occur.

Address

 

RelAdr

Relative Address. This drive does not support this feature; the field must be 0.

 

 

Transfer Length

The number of contiguous logical blocks of data to write. The drive returns CHECK

CONDITION status with the correct sense data if the specified transfer would cause the

 

write operation to extend beyond the Logical Block Address space.

Maxtor Atlas 10K V

5-149