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HISTORY OF COMPUTERS

WHAT IS A COMPUTER?

A computer is an electronic device which is capable of handling large amounts of data and possesses characteristics such as high speed, accuracy and ability to store a set of instructions (program) for solving a problem.  Computers can perform a veriety of mathematical calculations. They can repeat a complicated mathematical calculation million times without error. They can sort data, merge lists, search files and make logical decisions and comparisons. However, computer is devoid of any original thinking. It does nothing but what it is told to do. The computer is provided with a set of instructions called a program which controls all the operations of the computer.

The second half of the 20th century has come to be known as the “Age of computers”. The human fingers, the first device used for computation, gave way to the ABACUS, the first example of a digital computer.  Joseph Jacquard in 1801, was responsible for taking the first major step in the development of computers. He became the forerunner of the punched cards still in use today. Charles Babbage’s “Differential Engine” completed in 1833, proved to be the fundamental basis for the development of the modern computer and he is rightly called “the father of the computers”. In 1890 Hermwn Hollertith continued the work and devised a coding system to be punched on cards to represent data. He started selling his machines and the company he founded is now called the International Business Machines (IBM).

TYPES OF COMPUTERS

1) ANALOG COMPUTERS

They process data into a continuous form. This type of computer is useful for Scientific and Engineering applications in radar work, guided missiles and space programs. The main disadvantage of an Analog Computer is its accuracy factor and limited storage capacity. Hence, they are not suitable for processing business data.

2) DIGITAL COMPUTERS

They are capable of (a) storing data for processing; (b) performing logical operations; (c) editing or deleting the input data and (d) printing out the result at high speed. Hence, they are most suitable for business applications.

HARDWARE

It is a general term used to represent the physical components of the computer itself. It includes:- (1) Input devices (Keyboard) (2) Output devices (Printer) (3) Central Processing Unit (4) Back-up storage (DVD, Pen Drive)

SOFTWARE

It is a general term to describe all forms of programs associated with a computer. Without software, a computer is like a car without petrol. Following are 4 categories of software:  (1) Operating Systems  (2) Utility Programs  (3) Language Processors  (4) Application Programs

MEMORIES

(a) ROM (Read Only Memory): It provides the computer with a list of instructions for its operation.

(b) RAM (Random Access Memory): It provides instant access to any item of information stored in it.

HARD DISK CAPACITY

Hard Disk capacity is measured with Byte:

1024 Bytes = 1 Kilo Byte (KB)
1024 Kilo Bytes = 1 Mega Byte (MB)
1024 Mega Bytes = 1 Giga Byte (GB)
1024 Giga Bytes = 1 Terra Byte (TB)

PARTS OF COMPUTER

Monitor
CPU (Central Processing Unit)
Keyboard
Mouse (with mouse pad)
Pen Drive
CD Drive

NAMES ASSIGNED TO HARD DISK

(1) C
(2) D
(3) E
(4) F

NAMES TO FLOPPY & CD DRIVE

FLOPPY DRIVE
1) A
(2) B

CD Drive
G

WINDOWS DIFFERENT VERSIONS

Windows 3.1
Windows 95
Windows 98
Windows Me
Windows XP
Windows Vista
Windows 7
Windows 8
Windows 8.1
Windows 10
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Windows NT
Windows Server 2003
Windows Server 2008

Keyboard Shortcuts

Ctrl+O --> To Open
Ctrl+N --> To Create New
Ctrl+S --> To Save
Ctrl+F4 --> To Close
Alt+F4 --> To Shut Down
Shift+F10 --> Right Click
Ctrl+C --> To Copy
Ctrl+V --> To Paste
Ctrl+x --> To Cut
Ctrl+P --> To Print
Ctrl+Z --> To Undo
Alt+Equal --> Auto Sum
F7 --> To Correct Spelling
Shift+F7 --> To Show Dictionary
Alt+Tab --> To change Window
Alt+Space+N --> To minimize the Window
Alt+Space+X --> Maximize the Window
To Know the Weekdays: Type Date in A1 --> =Weekday(A1)