Kontron MSM800SEL User Manual
Page 51

MSM800SEV/SEL
/ Detailed System Description
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49
Location
Description
1Bh
Custom and Fixed (Hard) Drive Flags 
Bits 7-6 = Reserved 
Bit 5 
= Internal Floppy Disk Controller
0 = Disabled
1 = Enabled
Bit 4
= Internal IDE Controller
0 = Disabled
1 = Enabled
Bit 3
= Hard Drive 0 Custom Flag
0 = Disabled
1 = Enabled
Bit 2
= Hard Drive 0 IDE Flag
0 = Disabled
1 = Enabled
Bit 1
= Hard Drive 1 Custom Flag
0 = Disabled
1 = Enabled
Bit 0
= Hard Drive 1 IDE Flag
0 = Disabled
1 = Enabled
1Ch
Reserved
1Dh
EMS Memory Size Low Byte
1Eh
EMS Memory Size High Byte
1Fh - 24h
Custom Drive Table 0 
These 6 Bytes (48 bits) contain the following data: 
Cylinders 
10bits
range 0-1023
Landing Zone
10bits
range 0-1023
Write Precompensation 10bits
range 0-1023
Heads
08bits
range 0-15
Sectors/Track
8bits
range 0-254
1Fh
Byte 0 
Bits 7-0 = Lower 8 bits of Cylinders 
20h
Byte 1 
Bits 7-2 = Lower 6 bits of Landing Zone 
Bits 1-0 = Upper 2 bits of Cylinders 
21h
Byte 2 
Bits 7-4 = Lower 4 bits of Write Precompensation 
Bits 3-0 = Upper 4 bits of Landing Zone 
22h
Byte 3 
Bits 7-6 = Reserved 
Bits 5-0 = Upper 6 bits of Write Precompensation 
23h
Byte 4 
Bits 7-0 = Number of Heads 
24h
Byte 5 
Bits 7-0 = Sectors Per Track 
25h - 2Ah
Custom Drive Table 1 
These 6 Bytes (48 bits) contain the following data: 
Cylinders 
10bits
range 0-1023
Landing Zone
10bits
range 0-1023
Write Precompensation 10bits
range 0-1023
Heads
08bits
range 0-15
Sectors/Track
08bits
range 0-254
25h
Byte 0 
Bits 7-0 = Lower 8 bits of Cylinders 
26h
Byte 1 
Bits 7-2 = Lower 6 bits of Landing Zone 
Bits 1-0 = Upper 2 bits of Cylinders 
27h
Byte 2 
Bits 7-4 = Lower 4 bits of Write Precompensation 
Bits 3-0 = Upper 4 bits of Landing Zone 
28h
Byte 3 
Bits 7-6 = Reserved 
Bits 5-0 = Upper 6 bits of Write Precompensation 
29h
Byte 4 
Bits 7-0 = Number of Heads 
