Initialize Device Parameters (91H) - Hitachi T7K250 - Deskstar - Hard Drive Specifications

12.11 Initialize Device Parameters (91h)

Table 82: Initialize Device Parameters command (91h)
Command Block Output Registers
Register
Data
Feature
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Command
7 6 5
CRC UNC 0
0 0 0
The Initialize Device Parameters command enables the host to set the number of sectors per track and the number
of heads minus 1, per cylinder. Words 54–58 in Identify Device Information reflect these parameters.
The parameters remain in effect until the following events occur:
• Another Initialize Device Parameters command is received
• The device is powered off
• A soft reset/hard reset has occurred
• The Set Feature option of CCh instead of 66h is set.
Output parameters to the device
Sector Count
H
The following condition needs to be met to avoid invalid number of cylinders beyond FFFFh:
(Total number of user addressable sectors)/((sector count) x (H+1)) = < FFFFh
The total number of user addressable sectors is described in Identify Device command.
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
V V V V V V V V
- - - - - - - -
- - - - - - - -
- - - - - - - -
1 - 1 D H H H H
1 0 0 1 0 0 0 1
Error Register
4 3 2 1
IDN 0 ABT T0N AMN
0 0 V 0
This indicates the number of sectors per track. Zero (0) means that there are no sectors
rather than 256 sectors per track.
This indicates the number of heads minus 1 per cylinder. The minimum is 0 and the maxi-
mum is 15.
Deskstar T7K250 Hard Disk Drive Specification
Command Block Input Registers
Register
Data
Error
Sector Count
Sector Number
Cylinder Low
Cylinder High
Device/Head
Status
0 7 6
BSY RDY DF DSC DRQ
0 0 0
138
7 6 5 4 3 2 1 0
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
- - - - - - - -
see below
Status Register
5 4 3 2
COR IDX
0 - - 0
1 0
ERR
- V