Various Software Interrupts

Below are some of the BIOS Interrupts which might be useful in troubleshooting.....

Address(Hex) Interrupt Value Function
0000 00H Divide-by-zero intrr
0008 02H Non-maskable interr
000C 03H Breakpoint
0010 04H Arithmetic overflow
0014 05H Print screen
0018 06H Reserved
001C 07H Reserved
0020 08H Timer interrupt
0024 09H Keyboard service
0028 0AH VGA retrace
002C 0BH Serial port 2
0030 0CH Serial port 1
0034 0DH Hard disk
0038 0EH Floppy disk
003C 0FH Parallel port
0040 10H Video services
0044 11H Equipment check
0048 12H Memory size check
004C 13H Floppy and hard disk
0050 14H RS-232 service
0054 15H System services
0058 16H Keyboard
005C 17H Printer I/O
0060 18H Basic ROM entry point
0064 19H Initial Program Load
0068 1AH Time of day
006C 1BH Keyboard break
0070 1CH User timer
0074 1DH Monitor ROM pointer
007C 1FH Character generator
0088 22H DOS terminate address
008C 23H DOS Ctrl+Break exit
0090 24H DOS fatal error exit
0094 25H DOS absolute disk read
0098 26H DOS absolute disk write
009C 27H DOS Terminate
00A0 28H DOS idle loop
00A4 29H DOS console device
00A8 2AH DOS network
00B8 2EH DOS execute command
00BC 2FH DOS print spool control
00CC 33H Mouse driver calls
00FC 3FH LINK (internal use)
0100 40H Floppy and hard disk
0104 41H Pointer to hdd
0108 42H EGA video screen BIOS
010C 43H EGA initialize
0100 44H EGA graphics patterns
0114 45H Reserved
0118 46H Pointer to disk
011C 47H Reserved
0120 48H PCjr cordless keyboard
0124 49H PCjr non-keyboard scan

The interrupt vectors are stored in the RAM of your computer so that the values in the table can be changed. For example, a program or software driver may want to alter or update a BIOS routine to take advantage of a special feature of new hardware you install in your computer. The BIOS code itself loads default values for many of these interrupt vectors into the appropriate RAM locations with the vectors pointing at the routines stored in your computer's ROM.