class 9th Introduction of computer {computer notes} 1
Introduction to Computers
Computer
A Computer is an automatic electronic, calculating device which can process a given input in a prescribed manner to produce a desired output, at a very high speed with remarkable accuracy. It can also perform all arithmetic and logical functions according to instructions given in a systematic order to solve any problem and produce processed information.
Advantages of Computers
Speed
Since Computer is an electronic machine and electrical pulses travel at the rate of passage of electric current. This speed enables the computer to perform millions of calculations per second.
Storage
A computer has too much storage capacity. Once recorded, a piece of information can never be forgotten.
High Accuracy
A computer can be considered as 100% accurate. Checking circuits are built directly into the computer, that computer errors that undetected are extremely rare.
Versatility
Computer can perform any task, provided it can be reduced to a series of logical steps.
Diligence
Computer never gets tired. It performs most boring, repetitive and monotnous task.
Automatic Operation
Once a program is fed into computer the individual instructions are processed on after the other. Thus computer works automatically without manual intervention.
Obedience
The ability to take in and store a sequence of instructions for the computer to obey. Such a sequence of instruction is called a PROGRAM and it must be written in the Computer Language.
Decision Making Capability
Computer can take simple decisions, such as less than, greater than or equal to. It also determines whether a statement is true or false.
Hardware
the physical components and other attached input and output devices of computers are called Hardware. All Hardware components may be connected mechanically, electrically or electronically with each other. Hardware includes input/output devices, CPU, backing storage devices and electronic circuit.
Software
Computer required a number of instructions to do any job. The set of these instructions forms programs. Numbers of programs are combined for some purposes are called software.
They are designed by manufactures and programmers.
Types of Software
1. System Software
2. Application Software
Ages of Computer
At the early age people used pebbles, stones, sticks, scratches, symbols and finger tips to count, which were later replaced by numbers.
The history of computing is divided into three ages during which man invented and improved different types of calculating machines. These ages are,
Dark age - 300 BC to 1890
Middle age - 1890 AD to 1944
Modern age - since 1944 AD
Dark Age (3000 BC to 1890 AD
ABACUS
About 3000 years BC, Chinese developed the first calculating machine named Abacus or Soroban.
Abacus consists of a rectangular wooden frame having rods which carry round beads. Counting is done by shifting the beads from one side to another.
OUGHTRED’S SLIDE RULES
In 1632 AD William Oughtred, an English mathematician developed a slide rule. This device consists of two movable rules placed side by side on which number were marked.
PASCAL’S CALCULATOR
Blasé Pascal (1623-1662), a French developed the first mechanical calculating machine in 1642. This machine consists of gears, wheels and dials. It was capable of adding and subtracting operations.
GOTTEFRIED WILHOLM LEIBNITZ
In 1671, a German, Gottfried Von Leibnitz (1646-1716) improved Pascal’s calculator to make it capable of performing all maths operations.
JACQUARD’S LOOM
In 1801, a French, Joseph Marie Jacquard developed the first punch card machine.
BABBAGE DIFFERENCE ENGINE
Charles Babbage (1792-1871) an English mathematician also called Father of modern computer. As he gave the true concept of computer at Cambridge University, he developed Babbage Difference Engine in 1823 and Babbage Analytical Engine in 1833.
Lady Ada Augusta an assistant of Babbage is called the first programmer.
Middle Age (1890 AD TO 1944 AD)
DOCTOR HERMAN HOLLERITH
In 1880s Herman Hollerith an American developed a machine which used punch card system. The machine could sense and punch holes, recognize the number and make required calculations. This machine was first used in 1890s by American Census Bureau.
HOWARD AIKEN- MARK-1 COMPUTER
In 1937, Professor Howard Aiken build the first electro-mechanical computer Mark-1, by trying to combine Babbage’s theory and Hollerith’s punching technologies. He completed his project in 1944 with the help of IBM Engineers.
Mark 1 could multiply two, twenty digit numbers in 5 seconds and made a lot of noise. It had a shape like a monster about 50 feet long, 8 feet high, having wiring of length equal to distance from Lahore to Gilgit or Karachi to Bahawalpur (800km) and had thousand ends of electro-magnetic relays.
ABC (ATANASOFF BERRY COMPUTER)
ABC a special purpose computer was developed in 1938 by Dr. John Vincent Atanasoff and Clifford Berry at Iowa State College, USA.
Modern Ages (Since 1944 AD)
JOHN VON NEUMAN
In 1945, Dr. John Von Neuman suggested the concept of Automatic Data Processing (ADP) according to the stored program and data. ENIAC
(FIRST ELECTRONIC COMPUTER)
Electronic Numerical Integrator And Calculator (ENIAC) was the first electronic computer made in 1946 by John Presper Eckert and John Williams Mauchly, at the University of Pennsylvania, USA. This was based on decimal number system and it has no memory.
It could perform 5000 additions or 350 multiplications in one second. It contained 18000 vacuum tubes, 70,000 resistors, 10,000 capacitors and 60,000 switches and occupied a two room car garage. It consumed 150 kW of power. It weighed 27 tons.
EDSAC (FIRST STORED PROGRAM COMPUTER)
Electronic Delay Storage Automatic Computer (EDSAC) was first computer based on stored program concept. It was completed by Mourice Wilkes at Cambridge University in 1949.
EDVAC
Electronic Discrete Variable Automatic Computer (EDVAC) was built by John Williams Mauchly, John Presper Eckert at Moore School, Pennsylvania in 1951.
UNIVAC (FIRST COMMERCIAL COMPUTER)
UNIVersal Automatic Computer (UNIVAC) was the first commercially used computer made by John Presper Eckert and John Williams Mauchly in June 14, 1951.
Reply With Quote
Bookmarks