Functions of the Operating system
This is done by
routing the signals between the devices and the CPU.
Most computers have more than one input and output
device. Nowadays even the home computer may have a
mouse, keyboard and scanner attached, as well as a
screen, a printer and speakers.
Users print while they are still
looking at a display screen entering data and
commands. They may even listen to music emanating
from their computer speakers whilst working. This
multi-tasking is possible with the Windows operating
system
Allows the user to give commands to
the CPU in a user friendly way. Windows is an
operating system which uses a GUI interface as is the
Apple operating system. This interface is sometimes
called a WIMP
interface.
The user is informed when the printer
off-line or if it needs a paper refill. Other error
messages warn the user about not closing a file
before saving by always asking if it should be saved
ROM, the permanent memory is
available when the computer is switched on, but RAM,
the temporary memory must be reloaded each time. A
basic diagnostic program runs in ROM when the
computer is switched on and this is the boot program. It searches for
the operating system which is stored on disk, loads
it into RAM and activates it. Memory must be
allocated to allow the operating system to run
efficiently.
Memory is divided between all the
users on a network. Multi-user
operating systems such as Windows network versions
and Unix allow many users to share memory.
Files can be saved to disk and tape.
The operating system loads a file into memory and
performs the management programs like opening,
closing and saving of files.
Operating systems are supplied with
utility programs which carry out housekeeping
operations. These include back-up, deletion, copy and
listing programs, instructing the computer on setting configuration of defaults
such as the tracking speed of the mouse, the desktop
colours and the time display.
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