6.2.2Logical 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).

 

Physical sector

 

 

Physical cylinder 0

1

2

3

 

. .

LS

LS

 

 

 

 

 

Physical head 0

 

1

2

 

 

. .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LH0

62 63

64

 

. .

 

126

127

. .

189

190

 

. .

 

406

407

408

 

 

LS

LS

 

 

 

LS

LS

 

 

 

LS

LS

 

 

 

LS

SP

SP

 

 

63

1

 

. .

 

63

1

 

. .

 

63

1

 

. .

 

28

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LH1

LH2

 

 

 

 

 

 

 

 

Physical sector

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Physical cylinder 0

1

 

. .

 

35

36

 

. .

 

98

99

 

. .

 

161

162

. .

 

224

225

. . . .

 

407

408

 

LS

 

 

 

LS

LS

 

 

 

LS

LS

 

 

 

LS

LS

 

 

 

LS

LS

 

 

 

SP

SP

 

Physical head 1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

29

 

. .

 

63

1

 

. .

 

63

1

 

. .

 

63

1

 

. .

 

63

1

 

. . . .

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

LH6

 

LH7

 

LH8

LH9

 

 

. . . .

 

 

 

 

 

 

 

 

 

 

LH10

 

 

 

 

ex: Zone 0

Physical parameter

-Physical sector: 1 to 406 (For the rest, 2 spare sectors) Specification of INITIALIZE DEVICE PARAMETERS command

-Logical head: LH=0 to 14

-Logical sector: LS=1 to 63

Figure 6.5 Address translation (example in CHS mode)

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Image 174
Fujitsu MPD3XXXAT manual Logical address, Address translation example in CHS mode