The Bios Setup Utility; Irq Functionality - FIC PAK-2005 User Manual

The BIOS Setup Utility

The BIOS (Basic Input Output System) is the basic firmware that instructs the
computer on how to operate. For the BIOS to work properly, there must be a record
of the computer's hardware and configuration settings for it to refer to. This record is
created using the Setup Utility, a program that is stored permanently in the BIOS
ROM chip on the mainboard.
The system configuration record created by the Setup Utility is also stored on the
mainboard, but not permanently. This section of the memory it is stored in is the
NVRAM.
When you buy your computer, the system configuration record will already be set
and may in some cases differ from the basic defaults. The first time you use your
computer or when you need to re-configure your system, you should run the Setup
Utility and write down the settings. Please see Chapter 3 for an explanation on how
to run the Setup Utility.

IRQ Functionality

As you read through this manual, you will see the term IRQ on a number of
occasions. It is important for you to know what this term means, particularly if you
intend to upgrade your system.
IRQ stands for Interrupt Request, the process in which an input or output device
tells the processor to temporarily interrupt its current task and immediately process
something from the source of the interrupt. When it has completed this, the
processor returns to the task it was already processing. Devices that need an IRQ
line to operate sometimes need to have exclusive use of that line.
A large number of add-on cards, such as sound cards and LAN cards, require the use
of an IRQ line to function. Some number of IRQs may already be in use by
components in the system such as the keyboard and mouse. Add-on cards that need
to use an IRQ draw from the unused group of IRQs. When installing a card that uses
an IRQ, it will have a default IRQ setting which you might have to change if that
IRQ is already in use and cannot be shared.
An ISA add-on card may need to use IRQs. System IRQs are available to add-on
cards installed on the ISA bus. There are two categories of ISA add-on cards: so-
called Legacy ISA cards, which need to be configured manually and then installed in
the available ISA slot; and Plug and Play (PnP) ISA cards, which are configured
automatically by the system. As a result, when you install Legacy ISA cards, you
have to carefully configure the system to ensure that the installed cards do not
conflict with each other by having the same IRQ. With PnP cards, on the other hand,
IRQs are assigned automatically from the ones available in the system.
Overview
9