Basic Concepts of
Types of Computer.
Memory Storage & Computer Performance.
Data Communication & Networks.
Computer in Everyday Life.
Health & Environment.
Computer perform three main operations:
1) Receive input (Data raw facts).
2) Process it according to predefined
3) Produce output (information which
is meaning data).
The term hardware refers to the
physical components of your computer
such as the system unit, mouse,
keyboard, monitor… etc.
The software is the instructions
that makes the computer work.
Software is held either on your
computers hard disk, CD
DVD or on a diskette (floppy
disk) and is loaded (i.e. copied)
from the disk into the computers
RAM (Random Access Memory),
as and when required.
A person who uses the
software on the computer to do
A set of tools that are used to:
receive, process, store, retrieve, print
and transmit information in an
electronic form. These forms can be:
text, sounds, picture or video.
sized, Very powerful,
used by large organisations such
an banks to control the entire
business operation. Very
They are connected to a large
number of terminals that could
Do the same jobs as mainframe,
but smaller scale. They are used by
sized companies for specific
purposes, such as accounting.
Are high capacity, expensive, are
used for research and weather
forecasting, oil exploration
Cheap and easy to use. Often used
alone computers or in a
network. May be connected to
large mainframe computers within
A large Pc
type computer called
a Server is connected to smaller
PCs called Clients or Terminals,
therefore it is unable to work
It is small, briefcase
portable. It is powerful as PC but
It is hand
held computer, which is called a
Notepad with small screen and keyboard. It
performs some special functions and is
considered to be cheap.
Personal Digital Assistants (PDA):
Are small pen controlled, handheld
Can be used to send and receive faxes and E
mail, to write memos and to keep an
An intelligent terminal, for example a PC:
Performs a lot of the processing locally
You could use a PC, linked to a mainframe
A dumb terminal:
Has very limited processing capabilities itself,
but allows you to connect to a large powerful
computer such as a mainframe.
When you process your data from the dumb
terminal, it is the mainframe at the other
end of the network that is performing all the
IBM invented the PC (Personal Computer) way
The term PC compatible relates to PCs
manufactured by companies other than IBM
that are compatible with the traditional PC
In the early days, most PCs ran an operating
system called DOS (Disk Operating System).
These days most PCs will be running a
version of Microsoft Windows (Win
,Win XP,Win Vista).
The Apple Mac is a computer, but NOT a PC.
It uses a different operating system, and
requires special versions of application
In the early days the thing that really
distinguished the Mac over the PC was the GUI
(Graphical User Interface).