IBM PC BIOS and MS/PC-DOS Interrupt Services Summary Number Address Type Description ------- ------- ----.. -------------------------------------------- Int\00 00-03 CPU Divide by Zero Int\01 04-07 CPU Single Step Int\02 08-0B CPU Nonmaskable Int\03 0C-0F CPU Breakpoint Int\04 10-13 CPU Overflow Int\05 14-17 BIOS Print Screen Int\06 18-1B hdw Reserved Int\07 1C-1F hdw Reserved Int\08 20-23 hdw Time of Day Int\09 24-27 hdw Keyboard Int\0A 28-2B hdw Reserved Int\0B 2C-2F hdw Communications (8259) Int\0C 30-33 hdw Communications Int\0D 34-37 hdw Disk Int\0E 38-3B hdw Diskette Int\0F 3C-3F hdw Printer Int\10 40-43 BIOS Video I/O - services to handle video output Int\11 44-47 BIOS Equipment Check Int\12 48-4B BIOS Memory Int\13 4C-4F BIOS Diskette/Disk Int\14 50-53 BIOS Serial Communications Int\15 54-57 BIOS Cassette, System Services Int\16 58-5B BIOS Keyboard Int\17 5C-5F BIOS Parallel Printer Int\18 60-63 BIOS ROM BASIC Loader Int\19 64-67 BIOS Bootstrap Loader Int\1A 68-6B BIOS Time of Day Int\1B 6C-6F BIOS Keyboard Break Int\1C 70-73 BIOS Timer Tick Int\1D 74-77 BIOS Video Initialization Int\1E 78-7B BIOS Diskette Parameters Int\1F 7C-7F BIOS Video Graphics Characters, second set Int\20 80-83 DOS General Program Termination Int\21 84-87 DOS DOS Services Function Request Int\22 88-8B DOS Called Program Termination Address Int\23 8C-8F DOS Control Break Termination Address Int\24 90-93 DOS Critical Error Handler Int\25 94-97 DOS Absolute Disk Read Int\26 98-9B DOS Absolute Disk Write Int\27 9C-9F DOS Terminate and Stay Resident Int\28 A0-FF DOS r Reserved for DOS Int\29 A4-A7 DOS * Fast Screen Write Int\2A A8-AB DOS Microsoft Networks - Session Layer Interrupt Int\2B AC-AF DOS r Reserved and unknown Int\2C B0-B3 DOS r Reserved and unknown Int\2D DOS r Reserved and unknown Int\2E DOS r Reserved and unknown Int\2F DOS Multiplex Interrupt Int\30 DOS * Far jump instruction for CP/M-style calls Int\31 DOS r Reserved and unknown Int\32 DOS r Reserved and unknown Int\33 DOS Used by Microsoft Mouse Driver Int\34 DOS r Reserved and unknown Int\35 DOS r Reserved and unknown Int\36 DOS r Reserved and unknown Int\37 DOS r Reserved and unknown Int\38 DOS r Reserved and unknown Int\39 DOS r Reserved and unknown Int\3A DOS r Reserved and unknown Int\3B DOS r Reserved and unknown Int\3C DOS r Reserved and unknown Int\3D DOS r Reserved and unknown Int\3E DOS r Reserved and unknown Int\3F DOS r Reserved and unknown Int\40 100-103 BIOS r Hard Disk BIOS Int\41 104-107 BIOS r Hard Disk Parameters (except PC1) Int\42 108-10B BIOS r Pointer to screen BIOS entry (EGA, VGA, PS/2) Int\43 10C-10F BIOS r Pointer to EGA initialization parameter table Int\44 110-113 BIOS First 128 Graphics Characters Int\45 114-117 BIOS r Reserved by IBM (not initialized) Int\46 118-11B BIOS Pointer to hard disk 2 params (AT, PS/2) Int\47 11C-11F BIOS r Reserved by IBM (not initialized) Int\48 120-123 BIOS PCjr Cordless Keyboard Translation Int\49 124-127 BIOS PCjr Non-Keyboard Scancode Translation Table Int\4A 128-12B BIOS r Real-Time Clock Alarm (Convertible, PS/2) 4B-59 12C- BIOS Reserved for BIOS Int\5A 168-16B BIOS r Cluster Adapter BIOS entry address Int\5B 16C-16F BIOS*r IBM (cluster adapter?) Int\5C 170-173 BIOS NETBIOS interface entry port 60-67 180-19F User Program Interrupts (availible for general use) Int\60 10-Net Network Int\67 LIM & AQA EMS, EEMS 68-7F 1A0-1FF Reserved by IBM Int\6C System Resume Vector (Convertible) Int\6F some Novell and 10-Net API functions irq08.htm">Int\70 IRQ08 Real Time Clock Interrupt (AT, PS/2) irq09.htm">Int\71 IRQ09 LAN Adapter 1 irq10.htm">Int\72 IRQ10 (AT, XT/286, PS/2) Reserved irq11.htm">Int\73 IRQ11 (AT, XT/286, PS/2) Reserved irq12.htm">Int\74 IRQ12 Mouse Interrupt (PS/2) irq13.htm">Int\75 IRQ13 Coprocessor Error irq14.htm">Int\76 IRQ14 Hard Disk Controller (AT, PS/2) irq15.htm">Int\77 IRQ15 (AT, XT/286, PS/2) Reserved Int\7C IBM REXX88PC command language 80-85 200-217 ROM BASIC 86-F0 218-3C3 Used by BASIC Interpreter When BASIC is running F1-FF 3C4-3FF Reserved by IBM Interprocess Communications Area Int\F8 ICA *r Set Shell Interrupt (OEM) Int\F9 ICA *r OEM SHELL service codes Int\FA ICA r USART ready (RS-232C) Int\FB ICA r USART RS ready (keyboard) Int\FE ICA *r used on '283 & '386 Int\FF ICA *r used on '283 & '386