Overview of a Computer System
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Back to: COMPUTER SCIENCE SS1
Welcome to class!
In today’s class, we will be talking about the overview of a computer system. Enjoy the
class!
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What is a computer?
Constituents of a computer
Characteristics of a computer
What is a Computer?
A computer is a mechanical program’s machine that accepts data as input, store and
manipulates the data through instructions to give output as information.
A Computer is an electronic device known to be a very powerful tool for processing data
into meaning information in a faster, neater and cheaper form. The Computer System is
one that can take a set of inputs, process them and create a set of outputs.
A Computer is a general-purpose device that can be programmed to carry out a set of
arithmetic or logical operations automatically. Since a sequence of operations can be
readily changed, the computer can solve more than one kind of problem. Conventionally,
a computer consists of at least one processing element, typically a central processing unit
(CPU), and some form of memory.
An INPUT consists of data or commands that are entered into the computer usually via
an input device such as a keyboard, mouse, scanner etc. The role of an input is to
provide data for further processing.
Processing is the stage where the input data is manipulated to produce meaningful
information. Processing can include a number of stages, sorting, searching, calculating,
graphing etc. The result obtained is called output.
An OUTPUT is a stage where information received via processing is presented to the
user in a suitable format. Most outputs involve converting digital data to a physical effect
which a person can see or hear. You might be able to see your output via a printout or a
display and also hear via music, voice training instructions.
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Constituents of a computer
The computer system has two main parts namely
1. Computer hardware
2. Computer software
Computer hardware:
This refers to the physical things of a computer, things that can be seen, touched and
handled. Example – the system unit and peripherals.
1. The system unit: This is the combination of the major parts of the computer which
includes CPU, motherboard, RAM, ROM, chipsets, power module, CMOS battery
etc.
2. The peripherals: These are hardware parts used to enhance the capabilities of the
computer or improve its performance. E.g. keyboard, mouse, joystick, light pen,
scanner, monitor, speaker, printer etc.
Self-evaluation:
1. Explain what a computer is?
2. Mention 2 constituents of a computer?
Computer software:
It is a set of instructions or programs that direct the operation of the computer and
devices attached to it. Computer software is any set of machine-readable instructions that
directs a computer’s processor to perform specific operations. The computer software
contrasts with computer hardware, which is the physical component of computers.
The computer software can be divided into two – the system software and the application
software.
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1. System software: These are software used in performing basic tasks to manage a
computer system. E.g. Windows 95, 98, 2000, XP, Vista, Windows 8, Linux,
computer antivirus, basic input-output systems, device drivers.
2. Application software: These are software used to perform a specific task,
processing data in the computer. Application software uses the computer system to
perform special functions or provide entertainment functions beyond the basic
operation of the computer itself. There are many different types of application
software, because the range of tasks that can be performed with a modern
computer is so larger E.g. Ms word – for typing documents, Ms Excel – For
accounting, Adobe Photoshop – for editing pictures, Corel draw – for graphics
designing, Ms PowerPoint+ – For slide presentations.
3. Malicious software or malware – They are computer programs developed to harm
and disrupt computers. As such, malware is undesirable. Malware is closely
associated with computer-related crimes, though some malicious programs may
have been designed as practical jokes.
Characteristics of a computer
1. Accuracy and precision
2. High speed of operation
3. Reliability
4. Versatility
5. Automation
6. Speed
7. Storage.
General self-evaluation
1. Explain the term “Computer Hardware”.
2. Explain the term “Computer Software”.
3. What are the components of computer hardware?
4. List three output services.
In our next class, we will be talking about the History of Computer. We hope you
enjoyed the class.
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