A computer is defined as a powerful machine that can perform arithmetic and non-arithmetic operations quickly and accurately on any data. A program contains instructions that direct the computer to produce desired results. If incorrect data or programs are used, the output will be incorrect. Computers have characteristics like speed measured in nanoseconds and picoseconds, nearly 100% accuracy, 99.9% reliability, large memory and storage capacities. Computers are used in applications such as education, business, science, engineering, entertainment and more. The basic components include the central processing unit and system unit.

1. Computer Fundamentals Chapter 1

2. A computer is a very powerful and fast computing (calculating) machine. A computer can be defined as a device that can perform both arithmetic and non-arithmetic operations accurately on any data or information at a very high speed. The set of instructions given to the computer is called a program.

3. A program can be defined as a set of instructions, which directs the computer to produce the desired results. GIGO- Garbage In Garbage Out. Means if incorrect data is input to the computer system or an incorrect program acts on the data, the output will also be incorrect.

4. Speed Calculation Unit of Time Parts of a second Millisecond (ms) One-thousandth (1/1000) Microsecond (ms) One-millionth(1/1,000,000) Nanosecond (ns) One-billionth(1/1,000,000,000) Picoscon (ps) One-trillionth (1/1,000,000,000,000)

5. Characteristics of a Computer Speed: The speed of a computer in terms of nanoseconds and picoseconds. Accuracy: All computers have almost 100% accuracy. Reliability: Reliability of any computer system is typically in the range of 99.9%. Memory: It can store many data and easily to access them. Storage: It can hold huge numbers of data.

6. Basic Applications of Computers Schools Multimedia and hospital administration Ticketing Banks and Insurance Scientific and engineering applications Business and administrative applications Avionics and space flights Humanities Police Work Meteorology Entertainment

7. Components of a Computer System

8. The Central Processing Unit (CPU)

9. The System Unit