Configuration parameters

Interrupt vectors

Generally, each driver on your system, including those for network adapters and SLIP lines, must have its own interrupt vector (or ``IRQ''). An interrupt halts processing momentarily so that input/output or other operations can occur. Processing resumes after the specific operation takes place. Consequently, it is important that each device installed in your system be provided with an interrupt setting that does not conflict with the settings used by the hardware and other peripherals (unless the device in question supports sharing of interrupts).

Unless a device supports sharing of interrupts, its interrupt vector must not be used by any other device on the system. Refer to your networking hardware documentation to determine which vectors the hardware supports. The DCU (Device Configuration Utility) lists the hardware already installed on your system and what vectors are already in use.

NOTE: Some devices must be configured using SCOadmin managers; see ``Using configuration interfaces''. In particular, you must use the Network Configuration Manager to configure network adapters.

Standard hardware interrupt vectors (IRQs)

IRQ Description (driver) Notes
0 ~ Reserved
1 Keyboard driver (kd) Reserved
2 ~ Available (IRQ 2 is internally mapped to IRQ 9. When choosing IRQ values, you should consider IRQ 2 and IRQ 9 to be the same interrupt.)
3 Serial COM2 port (asyc) Reserved if present (unless disabled in the BIOS or with the DCU)
4 Serial COM1 port (asyc) Reserved if present (unless disabled in the BIOS or with the DCU)
5 Cartridge tape (ictha) or parallel port #2 (lp) Recommended cartridge tape setting if installing from non-SCSI cartridge tape drive and a printer is not assigned to this IRQ
6 Floppy disk (fd) Reserved
7 Parallel port #1 (lp) Required if present and used at that setting (unless disabled in the BIOS or with the DCU)
8 Real-time clock (rtc) Reserved
9 ~ Available
10 ~ Available
11 ~ Available
12 PS/2 mouse Reserved if PS/2 mouse us installed
13 Math coprocessor and programmable interrupt controller (atup) Reserved
14 Integral hard disk (dcd/athd) Only required if an IDE, ESDI, or ST506 hard disk is installed
15 ~ Available
To install a networking adapter and driver software, you must choose an interrupt vector (IRQ) setting for the adapter. Consult the adapter's documentation for acceptable IRQ settings.

After you determine your hardware's IRQ settings, choose settings for each networking adapter that you plan to install, making sure that the settings do not conflict with each other. The documentation for each networking adapter should indicate whether you need to configure the adapter physically to use the chosen IRQ setting. The operating system reserves interrupt vectors 4 and 7 for COM1 and lpt0, respectively. If you choose any setting that is either a setting reserved for another use or is in use by another device, a conflict occurs. Some SCOadmin managers may be able to detect conflicts.

If yours is an ISA system, your networking hardware might be preconfigured to use a particular vector. If you want to change this vector setting, you might also need to change the physical jumper settings on the adapter or run a setup program provided with the adapter.

NOTE: A number of networking adapters are preconfigured to use interrupt vector 3; the BIOS might also choose to use interrupt vector 3 on PCI or EISA buses. Your operating system has reserved IRQ3 for the asyc(7) serial I/O device. However, some BIOS setup programs permit IRQ reassignment; see your hardware documentation for more information.

© 2004 The SCO Group, Inc. All rights reserved.
UnixWare 7 Release 7.1.4 - 22 April 2004