Booting
in Computer
Starting
a computer or a computer-embedded device is called booting. Booting
takes place in two steps −
1.
Switching
on power supply
2.
Loading
operating system into computer’s main memory
3.
Keeping
all applications in a state of readiness in case needed by the user
The
BIOS (Basic Input Output System) software is built into the PC, and is the
first code run by a PC when powered on. When the PC starts up, the first job
for the BIOS is to initialize and identify system devices such as the video
display card, keyboard and mouse, hard disk drive, optical disc drive and other
hardware. The BIOS locates boot loader software and loads and executes that
software, giving it control of the PC. This process is known as booting, or
booting up.
BIOS
software is stored on a non-volatile ROM chip on the motherboard (it is often
called a ROM BIOS). This ensures that the BIOS will always be available and
will not be damaged by disk failures. Because RAM is faster than ROM, though,
many computer manufacturers design systems so that the BIOS is copied from ROM
to RAM each time the computer is booted, this is known as shadowing. Many
modern PCs have a flash BIOS, which means that the BIOS has been recorded on a
flash memory chip, which can be updated if necessary.
If a
system is already running but needs to be restarted, it is called rebooting.
Rebooting may be required if a software or hardware has been installed or
system is unusually slow.
There
are two types of booting –
1.
Cold Booting − When the system is started by
switching on the power supply it is called cold booting. The next step in cold
booting is loading of BIOS.
2.
Warm Booting − When the system is already running
and needs to be restarted or rebooted, it is called warm booting. Warm booting
is faster than cold booting because BIOS is not reloaded.
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