wHAT IS COMPUTER?
-> A machine that calculates.
WHAT do we USE computers?
->3 basic features:
-->1) Speed - calculates faster than humans
-->2) Memory - can store huge amounts of data
-->3) Accuracy - It can process accurately

->BASIC OPERATIONS of a computer system:
o Input
o Process
o Output

EVOLUTION of the computer system:
• 1st computer - Abacus
• 1st electronic computer - 1950's

-> Main electronic component - Vacuum tube

->DISADVANTAGES:
-->1) Huge expense
-->2) It generated enormous heat
-->3) No permanent storage device

• 2nd generation computers - 1960's
-> Main electronic component - transistors built with the technology of super-conductors. A lot of the problems were overcome, but one problem remained - there were still no permanent storage device.

• 3rd generation computers - 1970's
-> It had Integrated Circuits(IC)
-> Permanent storage device

• 4th generation computers - microcomputers - 1980's
-> Very large IC's
-> Computer System

• A system has integrated components. A computer system has four components:
-> 1) User - the people
-> 2) Programs - generally called the software
-> 3) Hardware
-> 4) Data

FOUR TYPES OF USERS:
-> 1) Primary Users: These are people who use programs and data to make decisions
-> 2) Secondary Users: They provide information to the primary users e.g. data entry operators, programmers

• We use data to get the information. There are various types of data. Two major types keys

-> (1) Function Keys (F1,F2, Home, PageUp) and
-> (2) Character Keys (a,b,1,2)

->3 TYPES OF CHARACTER KEYS
--> 1. Numeric
--> 2. Alphabetic
--> 3. Special (space. dot)

->3 TYPES OF DATA:
--> (1)Text Data is a combination of alphabetic letters, numbers and special characters
--> (2)Numeric Data - All digits
--> (3)Date/Time

-> HARDWARE SYSTEM

-> Computer hardware is a sub-system of a computer system like a traffic system is a sub-system of the road communication.
-> physical unites components of a computer system.

-> MAJOR HARDWARE COMPONENTS
-->(1) Input device
-->(2) Central Processing Unit (CPU)
-->(3) Output Device
-->(4) Memory
---> Primary memory stores only data which is needed for processing
---> Secondary memory stores permanent data

-> FUNCTIONS OF HARDWARE SYSTEM:
-->(1) Hardware components take inputs from the input devices
-->(2) It stores data in the memory
-->(3) Processes data in the central processing unit
-->(4) It provides output to the output device

INPUT DEVICE
->An input device takes input from the user. There are 4 major types of input devices:

-->(1) Keyboard: It sends data into the CPU by pressing keys. There are about 104-105 keys on a standard keyboard.
-->(2) Scanner: It scans printed material and data in both text and graphics, in single or multiple colors into the CPU. There are various sizes of a scanner.
-->(3) Optical Mark Reader (OMR): It reads answers on multiple choice questions and sends data int...

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