WHAT
IS AN OPERATING SYSTEM?
When you fire up your computer, one of the first programs
that starts is the operating system. It’s very obvious
to users because the first thing you usually see with
a modern operating system is the GUI (Graphical User Interface)
which shows you the programs, files and folders as icons
on a desktop. But the operating system is a lot more than
just the interface.
If
you think of an analogy with a car, the computer could
be considered to be the wheels, engine, steering, braking,
etc. The operating system then would be the thing between
the car and the driver that manages the car at a detailed
level for the driver. The driver doesn’t have
to work out how many millilitres of petrol to inject
into the carburetor at any given moment to get a certain
level of power, or how much brake fluid to inject into
the hydraulic lines to brake the car at a certain rate.
On a car these are mechanical control systems (though
almost all modern cars use microprocessors to control
the mechanics); on a computer the operating system is
what does this type of job.
Specifically,
operating systems will: manage the processor’s
time through scheduling; control the process currently
executing; manage input and output; organise the space
of storage disks; manage the computer’s memory;
control the competition between different processes
for the resources of the system. Modern multi-purpose
operating systems will also manage files; provide utility
programs and display the GUI.
Very
small and single-purpose computing systems, such as
your microwave oven, probably won’t have an operating
system. Larger, more complex systems will, particularly
those where many processes compete simultaneously for
the processor’s time, and a program (the operating
system) is needed to mediate amongst them.
|
