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System Resources
The following sections list system resources. See the vendor documentation delivered with an
expansion card or a peripheral device for instructions on how to use these resources.
ISA Bus Interrupt Request (IRQ) Assignments
IRQ
System Resource
IRQ
System Resource
0
Reserved (system timer)
8
Real-time clock
1
Reserved (keyboard)
9
Reserved
2
Reserved (interrupt controller)
10
Reserved
3
Serial port COM2 (default)
11
PCI-to-USB controller
4
Serial port COM1 (default)
12
PS/2 mouse
5
Sound processor
13
Reserved (math coprocessor)
6
Floppy disk controller
14
Primary IDE controller
7
Parallel port LPT1 (default)
15
Secondary IDE controller
Direct Memory Access (DMA) Channels
Channel
Assignment
Channel
Assignment
0
Sound processor
4
DMA controller
1
Sound processor
5
Open
2
Floppy disk controller
6
Open
3
Parallel port LPT1
7
Open
Input/Output (I/O) Addresses
Address (hex)
Description
0000 - 000F
Direct memory access controller 1
0020 - 0021
Interrupt controller 1
0040 - 0043
System timer
0060 - 0060
Standard 101/102-key keyboard
0061 - 0061
System speaker
0070 - 0071
Real-time clock
00A0 - 00A1
Interrupt controller 2
00C0 - 00DF
Direct memory access controller 2
00F0 - 00FF
Numeric data processor
