Computer Drive User Manual

C141-E056-01EN 6 - 7
6.2.2 Logical address
(1) CHS mode
Logical address assignment starts from physical cylinder (PC) 0, physical head (PH) 0, and
physical sector (PS) 1 and is assigned by calculating the number of sectors per track which is
specified by the INITIALIZE DEVICE PARAMETERS command. The head address is
advanced at the subsequent sector from the last sector of the current physical head address.
The first physical sector of the subsequent physical sector is the consecutive logical sector
from the last sector of the current physical sector.
Figure 6.5 shows an example (assuming there is no track skew).
LS
63
LH2LH1LH0
LS
2
LS
1
LS
1
243242241190189
64636232
12111
1
127126
Physical sector
Physical sector
ex: Zone 0
Physical parameter
- Physical sector: 1 to 241 (For the rest, 2 spare sectors)
Specification of INITIALIZE DEVICE PARAMETERS command
- Logical head: LH=0 to 14
- Logical sector: LS=1 to 63
Physical cylinder 0
Physical head 1
Physical cylinder 0
Physical head 0
LS
63
LS
1
LS
63
LS
1
SPSPLS
52
..
..
..
..
..
..
..
..
LH3
LS
63
LS
53
LS
1
LS
63
LS
1
LS
63
LS
1
LS
1
SPSPLS
63
..
..
..
..
..
..
..
..
....
....
....
LH4LH3 LH5 LH6
LH7
75 13813774 201200 243242
Figure 6.5 Address translation (example in CHS mode)