IBPS PO Computer Notes by Plutus Academy
Introduction to computer
2.Input and Output Devices
5.Computer Software and Operating System
8.Computer Networking 9. Internet and security
Introduction to Computer Notes by Plutus Academy
Definition : A computer is an electronic device which takes input from the user in the form of data(can be a sequence of numbers,characters,symbols,operand), then processed that data by performing some calculations and operations,after that it produced desired output(i.e. Meaningful information).
Data: Data are just raw material which does not convey any meaning to us.
E.g. like numbers ,characters,symbols,operand and text etc.
Information: Any meaningful thing that we get after processing(can be some calculations,comparisons or decisions) data is called information.
- The Term computer is derived from Latin word i.e ‘ computerae ’ which means ‘ to compute’ .
Tasks performed by computer- There are four major tasks that can a computer performs.
- Inputting- Takes data from the
- Processing- perform some operations on data.
- Outputting- Shows processed data i.e.
- Storing- stores your data/Information temporarily or permanently.
Devices used to perform Tasks –
1) Inputting – Keyboard,Mouse,Joystick,Scanner,Light Pen etc.
2 ) Processing – CPU(central processing unit).
3) Outputting – Monitor,Printer etc.
4) storing – Memory(RAM,ROM etc)
History of computer Evolution
1) Abacus- Invented by china in 16th century. First mechanical calculating device. Used for addition,subtraction and square roots.
2) ENIAC – Invented by JP Eckert and JW Mauchly in 1950. First electronic digital computer. Used for weather prediction, atomic energy calculation and other scientific uses.
3) EDSAC- Invented by John Von Neumann in the period of 1946-52 First computer which has storage capacity and capable of
Storing data and information. Also calculate table of squares and a list of prime numbers.
4) UNIVAC- Invented by JP Eckert and JW Mauchly in 1951. First general purpose electronic computer. Used magnetic tapes as input and output.
5) IBM-650- Invented by IBM company in 1954. Provided Input/Output units converting alphabetical and special characters to two-digit decimal code.
Generations of Computer– We have five generations till now
|I||1940 -1956||Vacuum tubes||Machine language||333 ms||Ex-ENIAC,UNIVAC-generate large amount of heat-Non portable -Fastest computing device -used for scientific purpose||BOS (batch OS)|
|II||1956 -1963||Transistors||Assembly and high level language||10 ms||Ex-PDP-8, IBM-1401-portable and generate less amount of heat -more reliable and less prone to hardware failure||Time sharing system,multi -tasking|
|III||1964-71||ICs||High level language(FORTRAN,C OBOL) Algol||100 ns||Ex- NCR-395, B6 500, DBMS||Real-Time system|
|IV||1971- Present||LSI (large scale integrated circuit)||PASCAL,ADA,COBOL – 74 FORTRAN IV||10 ps||Ex-Intel 4004 chip, Macintosh – More reliable and portable-better communication and resource sharing||Time sharing Network,GUI Interface|
|V||Present and beyond||SLSI (super large scale Integrated) chips||Artificial Intelligence ex-Robotics-parallel processing -Enable mega chips -Intel core microprocessor is implemented|
Terms Related to Computer
1) Hardware- Physical components of the computer system which performs specific task are called Ex-Monitor,CPU,Keyboard,Mouse etc.
2) Software-It is a set of programs and
3) Program-It is a set of instructions given to a computer by the user to perform particular
4) Data-Data are just raw material which does not convey any meaning to us. Ex-like numbers ,characters,symbols,operand and text etc.
5) Information-Any meaningful thing that we get after processing(can be some calculations,comparisons or decisions) data is called
6) Instruction-The command given by a user to computer to perform some particular task.
7) Memory-Memory stores our data/Information temporarily or permanently. It is a part of CPU.eg-RAM,ROM etc.
Classification of Computers
A) Based on Size
1) Micro Computer– Micro computer are very small in size.some of them are very handy.they are fastest growing and widely used Ex-PC(personal computer),Notebook,Palmtop,tablet and Smart phones.
2) Mini Computer-they are small in size,faster,cost lower than Mainframe. Initially ,the minicomputer was to designed to carry out some specific task like. Now they are using as a central computer known as Server.Ex-IBM-17,PDP-11. 3)MainFrame computer-these computer have large storing capacity and comprehensive range of software.It is considered as a backbone of network of computers and allow number of people to work at the same time. Ex-IBM-370,UNIVAC-1110
3) Super Computer-Super computers are most powerful,big in size,most expensive and fastest computers. The speed of super computers measured in FLOPS(floating point operation Per second). They are used in scientific research,nuclear research weather forecasting and research laboratories.
4) Analog Computer-Analog computer works on the data that is continuous in nature means which is not discrete And separated.This type of data is known as Analog Data eg-Voltage,speed,pressure,temperature,depth etc.they carry out arithmetic and logical operations by manipulating and processing data. Eg-Speedometers,seismograph,thermometer etc.
B) Based on Work
5) Digital Computer-Digital computer works on Discrete data that is which is not continuous in nature and when we are talking about discrete data in terms of digital computer then we are talking about binary data.as we know that binary data works only on 0 and 1 And it uses 0 and 1 to represent numerals,symbols and characters.Digital computer can perform arithmetic as well as logical operations.it works very fast and accurate. Ex-Calculator .
6) Hybrid Computer-It is a computer which has the feature of both Analog and digital computers.it can process both continuous as well as discrete Ex-Petrol pump processor,Machines in ICU to measure Temperature and BP.
7) General Purpose computer-General purpose computers are those computers that served us variety of services rather than specific Ex-Personal computer are best example of general purpose computer because it provides us variety of services.we can use it as a music player,as our notebook to write anything,as our PlayStation etc.
C) Based on Purpose-
8) Special purpose computer-this type of computer performs only specific task or you can say that are made to serve to solve only specific task or Eg -Navigational system in aircraft and traffic light control system.