1.1 1.2 1.3 Introduction
Introduction to Computers
Why Computer? Evolution of Computers
1.3.1 The First Computer 1.3.2 Some Well Known Early Computers 1.3.3 Computer Generations
1.4 1.5 1.6 1.7 1.8 1.9
Components of a Computer Hardware vs Software System vs Applications Software Bits and Bytes Input and Output Devices RAM/ROM
1.10 Secondary Storage Devices 1.11 Summary 1.12 Answers to SAQs
This unit aims at introducing you to today’s most commonly used electronic device – the computer. The study of this unit will highlight the characteristics and evolution of computers. It will also help you to understand the basic terminology associated with computers.
After studying this unit, you should be able to • • • • • • • • • understand the basic characteristics of computers, understand how the computers evolved, understand the components that make up a computer, differentiate between hardware and software, differentiate between system and application software, understand the difference between bits and bytes, classify devices as input and output devices, differentiate between ROM and RAM, and appreciate the use of various secondary storage devices.
1.2 WHY COMPUTER?
The word ‘Computer’ literally means to ‘Compute’ or to ‘Calculate’. Stated simply, it is an electronic device, which processes information based on the instructions provided, to generate the desired output. It, therefore, requires two
types of input – raw data, and the set of instructions to process or act upon the data. This can schematically be shown in Figure 1.1.
Data Process Instructions Input Output
Figure 1.1 : Processing Information
Data can be of any type – text, numeric, alpha-numeric, image, picture, sound etc. The instructions that act upon this data are also called the program or software in computer terminology.
1.2.1 Characteristics of Computers