o level computer notes

o level computer notes

o level computer notes. In this book, we will cover all topics from senior one up to s.4, From the introduction up to the last part topic of computing, enjoy

What is a Computer?   

It is an electronic device that performs tasks, such as mathematical calculations or electronic communication, under the control of a set of instructions called a program.

Characteristics of a Computer.

Speed: The computer is a very high-speed electronic device. The operations on the data inside the computer are performed through electronic circuits according to the given instructions.

Arithmetical and Logical Operations: A computer can perform arithmetical and logical operations. In arithmetic operations, it performs the addition, subtraction, multiplication, and division of numeric data. In logical operation, it compares the numerical data as well as alphabetical data.

Accuracy: In addition to being very fast, the computer is also a very accurate device. it gives accurate output results provided that the correct input data and set of instructions are given to the computer. It means that output is totally dependent on the given instructions and input data. If input data is incorrect then the resulting output will be incorrect. In computer terminology, it is known as garbage-in garbage-out.

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Reliability: The electronic components in modern computers have a very low failure rate. The modern computer can perform very complicated calculations without creating any problems and produces consistent (reliable) results.

Storage: A computer has internal storage (memory) as well as external or secondary storage. In secondary storage, a large amount of data and programs (set of instructions) can be stored for future use.

Retrieving data and programs: The data and programs stored on the storage media can be retrieved very quickly for further processing.

Automation: A computer can automatically perform operations without interfering with the user during the operations. It controls automatically different devices attached to the computer. It executes automatically the program instructions one by one.

Versatility: Versatile means flexible. Modern computers can perform different kinds of tasks one by one of simultaneously. It is the most important feature of a computer. At one moment you are playing a game on a computer, and the next moment you are composing and sending emails.

Communications: Today computer is mostly used to exchange messages or data through computer networks all over the world.

Diligence: A computer can continually work for hours without creating any error. It does not get tired while working after hours of work it performs the operations with the same accuracy as well as speed as the first one.

No Feelings: A computer is an electronic machine. It has no feelings. It detects objects on the basis of instructions given to it. Based on our feelings, taste, knowledge, and experience: we can make certain decisions and judgments in our daily lives. On the other hand, computers can not make such judgments on their own. Their judgments are totally based on instructions given to them.

Consistency: People often have difficulty repeating their instructions again and again. For example, a lecturer feels difficulty in repeating the same lecture in a classroom again and again. The computer can repeat actions consistently (again and again) without losing its concentration.

Precision: Computers are not only fast and consistent but they also perform operations very accurately and precisely. For example, in manual calculations and rounding fractional values (That is value with a decimal point can change the actual result). In computer, however, you can keep the accuracy and precision up to the level, you desire. The length calculations remain always accurate.

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