Specifications

Legacy BIOS References
165
Start
Location
Length
in
bytes
Description Modified by
Legacy BIOS
INT
Using It
Comments
0x75 1 Number of HDDs
attached
No 13
0x76 2 Reserved No 13
0x78 1 LPT 1 time-out Yes 14
0x79 1 LPT 2 time-out Yes 14
0x7A 1 LPT 3 time-out Yes 14
0x7B 1 Reserved No
0x7C 1 COM 1 time-out Yes
0x7D 1 COM 2 time-out Yes
0x7E 1 COM 3 time-out Yes
0x7F 1 COM 4 time-out Yes
0x80 2 Keyboard buffer start ptr 16
0x82 2 Keyboard buffer end ptr 16
0x84 7 Video info No 10
0x89 2 Reserved No
0x8B 1 Floppy media control Yes 13
0x8C 1 HDD Controller status Yes 13
0x8D 1 HDD Controller error
status
Yes 13
0x8E 1 HDD Interrupt control Yes 13
0x8F 1 Reserved No
0x90 1 Floppy 0 media status Yes 13
0x91 1 Floppy 1 media status Yes 13
0x92 1 Floppy 2 media status No? 13
0x93 1 Floppy 3 media status No? 13
0x94 1 Drive 0 current cylinder Yes 13
0x95 1 Drive 1 current cylinder Yes 13
0x96 1 Keyboard mode state &
flags
Yes 16
0x97 1 Keyboard LED flags Yes 16
0x98 2 User Wait flag offset Yes 15
0x9A 2 User wait flag segment Yes 15
0x9C 2 Low word of user wait
count
Yes 15
0x9E 2 High word of user wait
count
Yes 15
0xA0 1 Wait active flag Yes 15
0xA1 7 Reserved No
0xA8 4 Video info No 10