Class notes SJSDC5FS9

COMPUTER FUNDAMENTALS
 Computer is an advanced electronic device that takes raw data as an input from the user and processes it under
the control of a set of instructions (called program), produces a result (output), and saves it for future use.
 A computer is an electronic data processing device, which accepts and stores data input, processes the data
input, and generates the output in a required format.
FUNCTIONALITIES OF A COMPUTER
If we look at it in a very broad sense, any digital computer carries out the following five functions

 Step 1 − Takes data as input.
 Step 2 − Stores the data/instructions in its memory and uses them as required
 Step 3 − Processes the data and converts it into useful information.
 Step 4 − Generates the output.
 Step 5 − Controls all the above four steps.


Input Process Output


Computers are divided into different types based on different criteria.
A. Based on the size, a computer can be divided into five types:
1. Micro Computer
2. Mini Computer
3. Mainframe Computer
4. Super Computer
5. Workstations
1. MICRO COMPUTER
 It is a single-user computer which has less speed and storage capacity than the other types.
 It uses a microprocessor (A microprocessor is a computer processor where the data processing logic and
control is included on a single integrated circuit, or a small number of integrated circuits) as a CPU.
 The first microcomputer was built with 8-bit microprocessor chips.
 The common examples of microcomputers include laptops, desktop computers, personal digital assistant
(PDA), tablets, and smartphones.
 Microcomputers are generally designed and developed for general usage like browsing, searching for
information, internet, MS Office, social media, etc.
2. MINI COMPUTER
 Mini-computers are also known as "Midrange Computers." They are not designed for a single user.
 They are multi-user computers designed to support multiple users simultaneously.
 So, they are generally used by small businesses.
 Individual departments of a company use these computers for specific purposes.
 For example, the admission department of a university can use a Mini-computer for monitoring the
admission process.
3. MAINFRAME COMPUTER
 It is also a multi-user computer capable of supporting thousands of users simultaneously.
 They are used by large government organizations to run their business operations as they can store and
process large amounts of data.
 For example, Banks, universities, and insurance companies use mainframe computers to store the data of
their customers, students, and policyholders, respectively.
4. SUPER COMPUTER
 Super-computers are the fastest and most expensive computers among all types of computers.

,  They have huge storage capacities and computing speeds and thus can perform millions of instructions per
second.
 The super-computers are task-specific and thus used for specialized applications such as large-scale
numerical problems in scientific and engineering disciplines including applications in electronics, petroleum
engineering, weather forecasting, medicine, space research and more.
 For example, NASA uses supercomputers for launching space satellites and monitoring and controlling them
for space exploration.
5. WORKSTATIONS
 It is a single-user computer.
 Although it is like a personal computer, it has a more powerful microprocessor and a higher-quality monitor
than a microcomputer.
 In terms of storage capacity and speed, it comes between a personal computer and minicomputer.
 Work stations are generally used for specialized applications such as desktop publishing, software
development, and engineering designs.
B. On the basis of data handling capabilities, the computer is of three types:
 Analogue Computer
 Digital Computer
 Hybrid Computer
1. ANALOGUE COMPUTER
 Analogue computers are designed to process analogue data (represented in a physical way). Analogue data
is continuous data that changes continuously and cannot have discrete values.
 Analogue computers directly accept the data from the measuring device without first converting it into
numbers and codes.
 They measure the continuous changes in physical quantity and generally render output as a reading on a
dial or scale.
 Speedometer and mercury thermometer are examples of analogue computers.
2. DIGITAL COMPUTER
 Digital computer is designed to perform calculations and logical operations at high speed.
 It accepts the raw data as input in the form of digits or binary numbers (0 and 1) and processes it with
programs stored in its memory to produce the output.
 All modern computers like laptops, desktops including smartphones that we use at home or office are
digital computers.
3. HYBRID COMPUTERS
 Hybrid computer has features of both analogue and digital computer.
 It is fast like an analogue computer and has memory and accuracy like digital computers.
 It can process both continuous and discrete data.
 It accepts analogue signals and converts them into digital form before processing.
 So, it is widely used in specialized applications where both analogue and digital data is processed.
 For example, a processor is used in petrol pumps that convert the measurements of fuel flow into quantity
and price.
 Similarly, they are used in airplanes, hospitals, and scientific applications.
GENERATIONS OF COMPUTERS
A generation of computers refers to the specific improvements in computer technology with time.
1. First Generation Computers
 The first generation (1946-1959) computers were slow, huge and expensive.
 In these computers, vacuum tubes were used as the basic components of CPU and memory.
 These computers were mainly depended on batch operating system (the users do not interact with the computer
directly) and punch cards.
 Magnetic tape and paper tape were used as output and input devices in this generation.
Some of the popular first-generation computers are;