Product manual

SCSI Description

5-34 Maxtor Atlas 10K IV

5.13.1 LOG SENSE Command Descriptor Block

The Command Descriptor Block for the LOG SENSE command is shown in Table 5-

43. Table 5-44 contains field descriptions.

Table 5-43 LOG SENSE Command Descriptor Block-Data Format

Table 5-44 LOG SENSE Command Descriptor Block-Field Descriptions

Bit

Byte

765 4 3210

0 Operation Code (4Dh)

1 Reserved PPC SP

2 PC Page Code

3–4 Reserved

5 – 6 Parameter Pointer

7 – 8 Allocation Length

9Control

Field Description

PPC

The Parameter Pointer Control bit controls the type of parameters that can be requested

from the drive. This bit must be 0, indicating that all log parameters for the specified page

(subject to the allocation length specified) are returned to the initiator.

The Save Pages bit specifies whether the parameters are to be saved. This bit must be 0,

indicating that no parameters are to be saved and are reset at power-on or by a TARGET

RESET.

The Page Control field defines the type of parameter values to be selected. The field must

be 01b indicating that the current values are to be returned. Mode 11b (return default val-

ues) is not supported because all counters have a default value of 0.

Page Code

The value specified as the Page Code determines the page to be returned. Table 5-42 con-

tains a list of supported log pages and their page codes.

Parameter Pointer This field is related to the PPC field. This bit must be 0.

Allocation Length

This specifies the number of bytes of data that the drive is allowed to pass during the

DATA IN phase. The requested page is truncated if its length exceeds the number of bytes

specified in this field.