5.48WRITE LONG Command (3Fh)

The WRITE LONG and READ LONG commands allow the initiator to issue raw reads and writes of physical sectors addressed as logical blocks with an assumed sector length of 512 bytes. These commands are used to verify the correction capability of the drive's ECC and to create defects of a known kind and location to verify the drive's recovery and bad sector handling policies. The data format and field descriptions are shown in Table 5-214and Table 5-215respectively.

Table 5-214WRITE LONG Command Descriptor Block-Data Format

Bit

7

6

5

 

4

 

3

 

2

1

0

Byte

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

 

 

 

 

Operation

Code (3Fh)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

1

 

 

 

 

Reserved

 

 

 

 

RelAdr

 

 

 

 

 

 

 

 

 

2 - 5

 

 

 

 

Logical Block Address

 

 

 

 

 

 

 

 

 

 

 

 

 

 

6

 

 

 

 

Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

7 - 8

 

 

 

Byte Transfer Length (578)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

9

 

 

 

 

Control

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Table 5-215WRITE LONG Command-Field Descriptions

Field

Description

 

 

RelAdr

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

Logical Block

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

Address

 

 

Must be 578. This value reflects the number of bytes spanned by the ECC, including

 

the ECC itself, rounded up to the next word (this is easiest understood in bits: 4096

 

data bits + 1 force error bit + 15 Logical Block Address bits + 16 cross check bits + 2

Byte Transfer

pad bits + 480 ECC bits + 6 pad bits that are not written to media but are only needed

for transfer = 4496 bits or 578 bytes). Any other value in this field results in a CHECK

Length

CONDITION status and the appropriate sense data.

 

The initiator should first issue a READ LONG, then modify the data portion only, and

 

then issue a WRITE LONG. It is also recommended that the drive be reformatted after

 

these commands are used.

5.49WRITE SAME COMMAND

The WRITE SAME command requests that the drive write the single sector of data transferred by the initiator to the medium mulitple times. The data format and field descriptions are shown in Table 5-11 and 5-12 Table respectively.

Maxtor Atlas 10K V

5-153