Introduction
Computers are becoming very common place. Many are guilty of taking them for granted the way we take cars for granted. One does not need to know about the internal combustion system of a car before learning to drive a car but it helps to understand how cars work particularly if you own a car. The same is true for computers. It is possible to use computers on a daily basis and be ignorant about many basic facts about them. The fact of the matter is we need not be ignorant when information is easily available. This lesson will help to put computers in perspective and help users understand the very tool that is so common today.
A computer literate person will understand the limitations of computers. They will not expect computers to solve every problem nor will they expect computers to provide information when accurate data is not available. Computer literate individuals know that a one day computer course cannot make them an expert computer user. They will also admit that the field of computer science is to large for any one person to be an expert in every aspect of computers. Besides, things change so quickly that yesterday's knowledge is not adequate for solving today's problems. So what do we do? Whether you like computers or not is irrelevant. If you work with computers on a regular basis it is necessary to update your skills on an ongoing basis or you will soon be embarrassed even by children.
WHAT IS A COMPUTER?
A computer is an automatic, electronic data processing machine. It takes data as input, transforms these data into information by executing a stored program.
It is a sophisticated tool used by people to aid in problem analysis and problem solving.
There are analog computers and digital computers. Analog computers are designed to measure input rather than count input as in the case of digital computers. Analog computers are outside the scope of this lecture.
A digital computer accomplishes its tasks by counting. Because of how digital computers work internally they are said to be bi-state devices ( 0 or 1 ). Another way of categorizing computers is according to size and processing power. Here is a list of the categories of computers available today beginning with the largest and most powerful : There are Super-computers, mainframe computers, minicomputers and micro computers.
Supercomputers are the largest, most costly and most powerful. They are used mainly for nuclear simulation and weather forecasting.
Mainframe computers are large, costly and require a team of well trained staff to operate. They are often used by large financial institutions with heavy data processing needs.
Mini-computers are scaled down versions of mainframes. They were used mainly by smaller enterprises which could not justify the expense associated with the high operating cost of a mainframe ( micro-computers have now replaced minicomputers ). Mini-computers are now obsolete.
Microcomputers are the smallest and least costly. They are the common home computers which are often referred to as PCs or Personal Computers. At one time micro computers were the least powerful but because of advances in hardware technology many high end microcomputers out-perform older mini computers.
THE THREE BASIC OPERATIONS OF COMPUTERS
A computer performs three basic operations. They are:
- Arithmetic operations ( + addition, - subtraction, * multiplication, / division )
- Logical operations ( > greater than, < less than, = equal to, >= greater than or equal to, <= less than or equal to)
- Storage and Retrieval operations
When ever the response to a question is yes or no / true or false, this is the kind of response one would get from a logical operation. What is your response to the question- " Is one more than two ? " If I were to write a computer program to display the answer to this question. The processing performed on the data would be a logical operation.
COMPUTERS NEED DATA
Data or unorganized facts and figures are collected from various sources. A digital computer takes raw, unorganized facts as input, transforms these data into information with the help of a computer program.
Data must be accurate to produce useful information.
If care is not taken to collect accurate facts then we would have collected garbage. It is not possible to convert garbage into information. If we collect garbage and process it we will not get information. We will only get garbage. This is called, Garbage In, Garbage Out or GIGO.
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