1.1 Overview of Computer Systems
1.1 The Parts of a Computer System
Let us first look at what a Computer and a Computer System is.
A computer can be classified as a device that takes in raw data as input and processes
it and provides information as the output. The computer also has the ability to store data
and information.
The computer system consists of hardware (Physical components), software and users
(people who use the computer) that are necessary to make the computer function and to
processes data in a meaningful way and store data.
The physical organisation of devices and the organisation according to functionality
of a computer system can be developed by reference to the above definitions. Figure 1.1
and figure 1.2 can be used to illustrate this physical and functional organisation of a
computer system.
A study of the figure 1.1 and figure 1.2 shows that a computer system has four clear
categorisations for hardware and functionality of that hardware. They can be listed as:
Figure 1.1: Hardware components of a computer
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Figure 1.2: Logical design of the components of the computer
1. Processor, memory and integrating devices
2. Input devices
3. Output devices
4. Storage devices
All hardware components in a computer can be put into one of these four categories.
Following are some of the hardware devices that are commonly found in modern day
computer.
Processor, memory and integrating devices
• Central Processing Unit (CPU)
• Motherboard or Main board
• Main Memory
• Power supply
• VGA card
• Sound card
• LAN Card
• TV Card
Input Devices
• Keyboard
• Pointer device (e.g. Mouse, track-ball)
• Joystick and Game Pads
• Scanner
• Microphones, Still Digital Cameras and Video Cameras
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Output Devices
• Monitor and LCD Panel
• Printers
• Speakers
• Plotters
Storage Devices
• Hard drives
• DVD and CD ROM
• Tape Drives
• Flash Disks and Memory Cards
• Floppy disks
Computer Hardware
This section gives a description of the features and the functionality of the parts of a
computer.
The processor
The human brain can be considered as the organ that does all the analysis of the
information we receive through our five senses: sight, smell, touch, hearing and taste
(figure 1.3). It then produces appropriate responses to the information we received. The
information received by the brain, the thoughts and ideas it generated is retained in the
brain. Further more it is the organ that controls the functionality of our body’s organs and
parts. The brain is also capable of independent and creative thought and the generation of
new ideas. The human brain learns some of its functionality and control through
experience (learning) and some through instinct.
Figure 1.3: The Human Brain and its Sensors
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The computer’s equivalent to the brain is referred to as the processor. It is capable of
receiving information from its input devices and then processing that information and to
provide an output (figure 1.4). It also has the capability to store this information in a
storage device. The processor is responsible for controlling the various devices of a
computer.