1. Computer

2. Computer is an electronic device that is designed to work with Information. The term computer is derived from the Latin term ‘computare’, this means to calculate or programmable machine. Computer can not do anything without a Program. It represents the decimal numbers through a string of binary digits. The Word 'Computer' usually refers to the Center Processor Unit plus Internal memory.
Charles Babbage is called the "Grand Father" of the computer. The First mechanical computer designed by Charles Babbage was called Analytical Engine. It uses read-only memory in the form of punch cards.
Computer is an advanced electronic device that takes raw data as input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non- numerical (arithmetic and logical) calculations.

3. Characteristics of Computer

4. Characteristics of Computer
Automatic
Speed
Accuracy
Diligence
Versatility
Power of Remembering
No IQ (Intelligence quotient)
No Feeling

5. Automatic: A Machine is Set to be automatic
Automatic: A Machine is Set to be automatic. If it Works by it Self without human intervention. Computers are automatic machine because ones started all jobs they carry a job. until the jobs is finished normal without any assists. Whoever Computer being machine. Its Perform only the activities that it is instructed by the user.
Speed: A Computer is a very fast Devices its can Perform is in few second the amount if word that human being can do. In an Entire (if he work day and night and did noting as). A computer does in one minute. Work take a man his Entire lifetime the speed of computer is measured in terms of Millie seconds  (10-3), Micro Seconds (10-6), Nano- Seconds (10-9), and Even the Per Seconds (10-12).

6. Accuracy: In Edition to being very fast Computers are very accurate
Accuracy: In Edition to being very fast Computers are very accurate. The Accuracy of a Computer is Consistently. high and the Degree of accuracy of the particular Depended upon its Design. For a Particular Computers every calculation is Performed with the same accuracy. Error can Occur in a Computer but mainly. Due to human the technical weakness. Computers Error Caused due to incorrect input Data or Unreliable. Program are often refer to as Garbage in Garbage out (GEGO).
Diligence: Unlike human beings a computer is Free from monotony, tiredness and lack of concentrate. it can continuously work and without creating any Errors. Hence, Computer Score over human beings in Doing routine types of jobs which required great accuracy.

7. Versatility: Is a one of the most wonder full nature of computer
Versatility: Is a one of the most wonder full nature of computer. Computers can Performs different categories of jobs effectively. All That is required to change its talent is to/slip in a new program into it. A computer is capable if perform. almost any task is the task can be reduced to a series of logical steps.
Power of Remembering: A computer can store and recall any amount of information because of its secondary memory/storage (A type of Detachable memory) every peace of information can written as long as desired by the user and can be Recall as and when required even after several years.

8. No IQ (Intelligence quotient): A Computer is not a magical devices
No IQ (Intelligence quotient): A Computer is not a magical devices. its posses, not Intelligence of  its own. its IQ level is zero it has to be told what to do and what Sequence. Hence, Only the user can determine what's tasks a computer will performed. A computer can not take its own Decision in this regular.
No Feeling: Computer Are Devoid of emotions. they have no Feeling and No instincts, Because they are machine Only man have succeeded in building a memory for the computer but no computer passes. The equevent a human heart and seal.

9. Classification of Computer
(1)
Types of Computers on the basis of Hardware Design.
(2)
Types of Computers on the basis of Size and Capacity.
(3)
Classification of Computers on the Basis of Purpose.

10. Types of Computers on the Basis of Operation
Analog Computer
(1)
Digital Computer
(2)
Hybrid Computer
(3)

11. Analog Computer

12. Applications Analog computer Speedometer Weight machine Thermometer
Analog Computer is a computing device that works on continuous range of values.
The results given by the analog computers will only be approximate since they deal with quantities that vary continuously.
It generally deals with physical variables such as voltage, pressure, temperature, speed, etc.
Examples
Speedometer
Weight machine
Thermometer
Temperature
Speed
Applications
Engineering
Scientific Work
To control process
Chemical industries

13. Advantage & Disadvantages Of Analog Computer
ADVANTAGE OF ANALOG COMPUTERS
Analog computers are fast.
DISADVANTAGES OF ANALOG COMPUTERS
Analog computers are not accurate.
Analog computers lack memory.

14. Digital Computer

15. Digital Computers
On the other hand a digital computer operates on digital data such as numbers.
It uses binary number system in which there are only two digits 0 and 1. (a bit)
Digital Computers can give more accurate and faster results.
Digital computer is well suited for solving complex problems in engineering and technology.

16. Digital Computers (Cont…)
Hence digital computers have an increasing use in the field of design, research and data processing.
Based on the purpose, Digital computers can be further classified as:
General Purpose Computers:
Used for any type of applications.
Special Purpose Computers:
One that is built for a specific application.

17. Advantage & Disadvantages Of Digital Computer
ADVANTAGES OF DIGITAL COMPUTERS
Digital computers are accurate.
Store information.
DISADVANTAGES OF DIGITAL COMPUTERS
Digital computers are slow as compared to Analog computers.

18. Hybrid Computers

19. Hybrid Computers
A hybrid computer combines the desirable features of analog and digital computers.
It is mostly used for automatic operations of complicated physical processes and machines.
Now-a-days analog-to-digital and digital- to-analog converters are used for transforming the data into suitable form for either type of computation.
Hybrid computers are mainly used for specialized tasks.

20. Advantages Of Hybrid Computers
It combines the best features of both digital and analog.
Hybrid computers have the accuracy of analog and speed of digital computers
Applications
In hospitals
In Air Defence system

21. Types of Computers on the Basis of Size and Capacity
(1) Micro Computer
(2) Mini Computer
(3) Mainframe Computer
(4) Super Computer

22. Micro Computer

23. Microcomputer
A personal computer; designed to meet the computer needs of an individual.
Provides access to a wide variety of computing applications, such as word processing, photo editing, e- mail, and internet.

24. Mini Computers
Mini computers are lower to mainframe computers in terms of speed and storage capacity.
They are also less expensive than mainframe computers.
Some of the features of mainframes will not be available in mini computers. Hence, their performance also will be less than that of mainframes.

25. Micro Computers
The invention of microprocessor (single chip CPU) gave birth to the much cheaper micro computers. They are further classified into
Desktop Computers
Laptop Computers
Handheld Computers(PDAs)

26. Desktop Computers
Today the Desktop computers are the most popular computer systems. These desktop computers are also known as personal computers or simply PCs.
They are usually easier to use and more affordable.
They are normally intended for individual users for their word processing and other small application requirements.

27. Laptop Computers Laptop computers are portable computers.
They are lightweight computers with a thin screen.
They are also called as notebook computers because of their small size.
They can operate on batteries and hence are very popular with travellers.
The screen folds down onto the keyboard when not in use.

28. Handheld Computers
Handheld computers or Personal Digital Assistants (PDAs) are pen-based and also battery-powered.
They are small and can be carried anywhere.
They use a pen like stylus and accept handwritten input directly on the screen.
They are not as powerful as desktops or laptops but they are used for scheduling appointments, storing addresses and playing games.
They have touch screens which we use with a finger or a stylus.

29. Micro Computer Least powerful Widely used Four types Desktop
Notebook or laptop
Tablet PC
Handheld

31. Mainframe Computer

32. Mainframe Occupies specially wired, air-conditioned rooms
Large expensive computer capable of simultaneously processing data for hundreds or thousands of users.
Used to store, manage, and process large amounts of data that need to be reliable, secure, and centralized.
Usually housed in a closet sized cabinet.
Mainframe
Occupies specially wired, air-conditioned rooms
Capable of great processing speeds and data storage
Not as powerful as supercomputers

33. Modern Mainframe Computer

34. Super Computer

35. Super Computers
They are the best in terms of processing capacity and also the most expensive ones.
These computers can process billions of instructions per second.
Perhaps the best known super computer manufacturer is Cray Research.
Some of the "traditional" companies which produce super computers are Cray, IBM and Hewlett-Packard.
Muhammad Hammad Waseem

36. Applications & Uses Weather forecasting Stock analysis
Nuclear research
Designing complex machines
Scientific simulations
(animated) Graphics, analysis of geological data