Slides in this set
7 Operating Systems
An operating system is a set of programs that
controls how the hardware of a computer
An operating system provides a means of
communication between the user and the
computer, deals with the loading and running
of applications programs and manages the
transfer of data and files to and from
peripheral devices.…read more
The most widely used operating systems are called
Windows 2000, MacOS (for Apple Mac computers),
Novell Netware and UNIX.
The operating system that a computer has also
determines what applications software will run on it.
Applications software will only work on a computer
that has the operating system that it was designed to
be used with.
Applications software will not run on a computer that
has a different operating system to the one that it was
designed for.…read more
Functions of an operating system
It deals with input and output, which involves:
Accepting data from input devices and transferring it to
the computer's memory.
Making sure that any output is sent to the correct output
It manages the transfer of data between the computer's
memory and backing storage devices.
It manages system resources, which involves:
Allocating memory space to programs and data.
Keeping track of which parts of the memory have already
been allocated and the parts that are still free.…read more
It deals with the loading of applications software into
memory and controls the execution, or `running' of them.
It also provides a way for applications software to
communicate with the computer's hardware.
It deals with any errors that occur when a program is
being run, or when data is being transferred somewhere,
and informs the user if necessary.
It manages system security, which involves:
Monitoring and restricting access to programs and
Preventing unauthorised access to the system.
It provides a human computer interface, or HCI, for
the user.…read more
It provides special facilities for multiprogramming.
A multiprogramming operating system can hold more
than one program in memory at the same time. There
are two types of multiprogramming operating system;
multitasking, and multi-user.
A multitasking operating system allows two or more
programs to run at the same time. The operating
system does this by swapping each program in and out
of memory in turn. When a program is swapped out of
memory it is stored temporarily on disk until it is
needed again. Windows 2000 is an example of a
multitasking operating system.…read more