BIOS : Basic Input
Output System
** Hardware Guide Home **
BIOS: All computer
hardware has to work with software through an interface. The BIOS gives the
computer a little built-in starter kit to run the rest of softwares from floppy
disks (FDD) and hard disks (HDD). The BIOS is responsible for booting the
computer by providing a basic set of instructions. It performs all the tasks
that need to be done at start-up time: POST (Power-On Self Test, booting an
operating system from FDD or HDD). Furthermore, it provides an interface to the
underlying hardware for the operating system in the form of a library of
interrupt handlers. For instance, each time a key is pressed, the CPU (Central
Processing Unit) perform an interrupt to read that key. This is similar for
other input/output devices (Serial and parallel ports, video cards, sound cards,
hard disk controllers, etc...). Some older PC's cannot co-operate with all the
modern hardware because their BIOS doesn't support that hardware. The operating
system cannot call a BIOS routine to use it; this problem can be solved by
replacing your BIOS with an newer one, that does support your new hardware, or
by installing a device driver for the hardware.
See Also : CMOS
Setup
Setup is the set of procedures
enabling the configure a computer according to its hardware caracteristics. It
allows you to change the parameters with which the BIOS configures your chipset.
The original IBM PC was configured by means of DIP switches buried on the
motherboard. Setting PC and XT DIP switches properly was something of an arcane
art. DIP switches/jumpers are still used for memory configuration and clock
speed selection. When the PC-AT was introduced, it included a battery powered
CMOS memory which contained configuration information. CMOS was originally set
by a program on the Diagnostic Disk, however later clones incorporated routines
in the BIOS which allowed the CMOS to be (re)configured if certain magic
keystrokes were used.
Unfortunately as the chipsets
controlling modern CPUs have become more complex, the variety of parameters
specifiable in SETUP has grown. Moreover, there has been little standardization
of terminology between the half dozen BIOS vendors, three dozen chipset makers
and large number of motherboard vendors. Complaints about poor motherboard
documentation of SETUP parameters are very common.
To exacerbate matters, some
parameters are defined by BIOS vendors, others bychipset designers, others by
motherboard designers, and others by various combinations of the above.
Parameters intended for use in Design and Development, are intermixed with
parameters intended to be adjusted by technicians -- who are frequently just as
baffled by this stuff as everyone else is. No one person or organization seems
to understand all the parameters available for any given SETUP.
