Initialize Device Parameters (91H) - IBM DBCA-204860 - Travelstar 4.8 GB Hard Drive Specifications

12.10 Initialize Device Parameters (91h)

C o m m a n d B l o c k O u t p u t R e g i s t e r s
R e g i s t e r
D a t a
F e a t u r e
S e c t o r C o u n t
S e c t o r N u m b e r
C y l i n d e r L o w
C y l i n d e r H i g h
D e v i c e / H e a d
C o m m a n d
E r r o r R e g i s t e r
7 6 5
C R C U N C 0 I D N
0 0 0
Figure 75. Initialize Device Parameters Command (91h)
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 reflects these parame-
ters.
The parameters remain in effect until the following events:
Another Initialize Device Parameters command is received.
The device is powered off.
Hard reset occurs.
Soft reset occurs and the Set Feature option of CCh is set instead of 66h.
Output Parameters To The Device
Sector Count The number of sectors per track. 0 does not mean there are 256 sectors per track,
but there is no sector per track.
H The number of heads minus 1 per cylinder. The minimum is 0 and the maximum is
15.
Note: The following condition needs to be satisfied to avoid invalid number of cylinder beyond F F F F h ,
which will cause performance degradation of the drive.
(Total customer usable data sectors) / ((Sector Count)*(H+1))
The total customer usable data sectors are indicated at 3.1, " Logical Drive Format" on page 9,
and related description is at 10.3.1, "Logical CHS Addressing Mode" on page 69.
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O E M Specifications of DBCA-2xxxxx 2.5 inch H D D
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
4 3 2 1 0
0 A B T T 0 N A M N
0 0 V 0 0
C o m m a n d B l o c k I n p u t R e g i s t e r s
R e g i s t e r 7 6 5 4 3 2 1 0
D a t a
E r r o r
S e c t o r C o u n t
S e c t o r N u m b e r
C y l i n d e r L o w
C y l i n d e r H i g h
D e v i c e / H e a d
S t a t u s . . . S e e B e l o w . . .
S t a t u s R e g i s t e r
7 6 5 4 3
B S Y R D Y D F D S C D R Q C O R I D X E R R
0 0 0
→
FFFFh
2 1 0
0 V