1. Types of Computers On the basis of principle of construction
Computers are divided into three types:
Analog Computers
Digital Computers
Hybrid Computers

2. Analog Computers
A computer in which numerical data are represented by measurable physical variables, such as electrical voltage.
An analog computers is a form of computer that uses the continuously changeable aspects of physical phenomena such electrical, mechanical, or hydraulic quantities to model the problem being solved.
As mechanical computers used in World War Second II for controlling gun fire.
Analog computers are also used in science and industry.
Analog computers deal with measure data.
Examples: 1. Thermometer because it measures the length of a mercury column, which varies continuously.
2. Analog Clock
3. Car Speedometer

3. Digital Computers
A digital computer is an electronic computing machine that uses the binary digits(bits) 0 and 1 to represent all forms of information internally in digital form.
Every computer has a set of instructions that define the basic functions it can perform.
Sequences of these instructions constitute machine-language (Low level language in the form of 0’s and 1’s )programs that can be stored in the computers.
Examples:
1. Calculator (a small computer)
2.Digital clock, Digital watches
3. Weighing machines
4. Consumer electronic equipment (such as microwave oven )
5. Automobiles
6. Mini, Micro, Mainframe and super computers.

4. Diff b/w : Analog and Digital Computers
Analog computer works with continuous values.
Digital computers works with discrete value (0,1). It can work only with digits
It has very limited memory.
It can store large amount of data.
It has no state.
It has two states on and off
It can perform certain types of calculations.
Its speed of calculation is very high.
It is difficult to use
It is easy to use.
Analog computers is used in engineering and scientific applications.
Digital computer is widely used in almost all fields of life.
Analog computer is used for calculations and measurement of physical quantities such as weight, height, temperature and speed.
Digital computer is used to calculate mathematical and logical operations.
Its accuracy is high.
Its accuracy is comparatively low.
Its readability is low.
Its readability is high.
Examples: Thermometer, analog clock, older weighing machines. Car speedometer, voice , radio/tv signal etc.
Examples: digital watches, digital weighing machines, mini computers, microcomputers, mainframe computers and super computers.

5. Hybrid Computers Examples:
Hybrid computes are computers that exhibit features of analog computers and digital computers.
The digital component normally serves as the controller and provides logical operations.
The analog component normally serves as a solver of differential equations.
Examples:
An example of a hybrid computer system is a cement plant where all calculations are made by digital systems(digital computers) and accordingly actions such ass increase of certain material in the furnace and increase / decrease of fuel for temperature is performed by the help of analog system.
Gas Pump Station (where measurement of gas by analog system, and displaying such calculation by digital system(computer).

6. Examples Analog Computers
The Water Integrator was an early analog computer built in the Soviet Union in 1928.
It functioned by careful manipulation of water through a room full of interconnected pipes and pumps.
A mechanical computer is built from mechanical components such as levers and gears, rather than electronic components.
An example of a hybrid computer is the computer used in hospitals to measure the heartbeat of the patient. the ECG monitor of a patient in a hospital. It takes in an analog signal that is the heartbeat of the patient and converts it into the digital format after processing it.

7. This particular Beckman Instruments EASE analog computer was 60 feet long and had a push button control panel. According to the Computer History Museum, this one was used by the Allison division of General Motors to design jet engines about 1962.

8. A 1960 Newmark analogue computer which comprised five components was used to solve differential equations.
In chemistry, they describe the rates of chemical reactions. Economists use differential equations to describe investment returns, sales practices

9. Classification of Digital Computers
Computers are classified according to sizes, speed and memory capacity. Computers are different types:
Super Computers
Mainframe Computers
Mini Computers
Micro/Personal Computers
Desktop Computes
Laptop Computers
Tablet Computers
Palmtop (handheld pc) Computers

10. Super Computers
Supercomputer are very fast computers that can perform hundreds of millions of instructions per second. These are the fastest calculating devices.
Uses:
Super computer are used by government agencies .
Used for scientific and engineering applications that must handle very large databases or do a great amount of computation.
Astronomers and space scientists use super computers to study the Sun and space weather.
Supercomputers are used in nuclear technology.
Supercomputers are used to research in the field of medicine. For example Cancer.
Supercomputers are used for the heavy stuff like weather maps, construction of atom bombs, finding oil, earthquake prediction, and sciences where a lot of calculations must be done.

11. World's Fastest Super Computers Ref: www.top500.org
RANK
SUPER COMPUTER NAME
SPEED 1
Tianhe-2 (MilkyWay-2)
National University of Defense Technology Manufacturer (NUDT)
Cores | 3,120,000
O/S | Kylin Linux
Power: 17, kW
Memory: 1,024,000 GB 2
Titan - Cray XK7
Oak Ridge National Laboratory
Manufacturer Cray Inc. USA
Cores | 560,640
O/S | Cray Linux Environment
Power: 8, kW
Memory: 710,144 GB 3
Sequoia - BlueGene/Q
IBM
Livermore – USA
Cores | 1,572,864
O/S | Linux
Power: 7, kW
Memory: 1,572,864 GB
A petaflop/s is equivalent to 1,000 trillion calculations per second.
China was rapidly becoming a "player" in high performance computing. China aims to become supercomputer superpower.

12. Tianhe-2 (MilkyWay-2)
Sequoia - BlueGene/Q
Titan - Cray XK7

13. Mainframe Computers Uses:
Mainframe computers are smaller than Super Computers. Usually, a main frame would occupy an entire room and could cost over million dollars.
The name comes from the way the machine is build up: all units (processing, communication etc.) were hung into a frame. Thus main computer is build into a frame, therefore it is called mainframe.
Mainframes are typically manufactured by large companies such as IBM, Hitachi etc.
Uses:
Mainframe computers are the big, powerful, expensive computers used in the background by most large organizations.
Mainframe computers are used to run commercial applications and other large-scale computing purposes.
It is also used in banking and insurance businesses where enormous amounts of data are processed.
For example millions of records , each day.

14. Mainframe Compuer

15. Mini Computers Uses: Minicomputers are relatively low cost and small .
This setup (mini Computers) allowed more people to have access to computers.
minicomputer is a class of multi-user Computer that lies in the middle range of the computing spectrum, in between the largest Multi-user systems (mainframe computer) and the smallest single-user systems (Microcomputers or personal computers.
Uses:
Mainframe computers are used to run commercial applications and other large-scale computing purposes.
It is also used in banking and insurance businesses where enormous amounts of data are processed.
For example millions of records , each day.

16. Mini Computer Name: PDP 7

17. Personal (Micro) Computers
The term “ microcomputer” came into popular use after the introduction of the minicomputer.
A personal computer (PC) is any general-purpose Computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end user.
A personal computer may be a desktop computer, a laptop, a tablet PC, or a handheld PC (also called a palmtop).
Software applications for personal computers include word processing, spreadsheets, databases, Web browsers and clients, games and special-purpose software applications.
A PC may be used at home or in an office. Personal computers may be connected to a local area network (LAN), either by a cable or a wireless connection.

18. Personal (Micro) Computers : Features
Cheap and easy to use:
Micro computers are cheap and easy to use.
Limited Support for I/O device
They support very limited input and output capacities.
Storage Capacity
They have less storage capacity
Software Capacity
These computers support very limited number of software
Architecture
Most of microcomputers are self-contained unit, which are light enough and can be moved easily.
Number of Operators
They are designed to be used by one person at a time.
I/O devices
In addition to CPU , a microcomputer has diff input / output devices like.

19. Personal (Micro) Computers : Features
Data Storage
Hard disk and floppy disk drivers are used to enter and store data and programs.
Softcopy Output
A visual display screen (monitor) and / or a printer is used to get the output.

20. Personal (Micro) Computers : Uses
Like other computers (super, mainframe, micro), personal computers can be instructed to perform a variety of individual functions.
A set of instructions that tells a computer what to do is called a program.
Today, thousands of application programs are available for use on personal computers. They include such popular programs as word processing programs, spreadsheet programs, database programs, and communication programs.
Desktop Computers
Today the desktop computers those computers which have the different desktop computer cases that can be laid on the desk and they are different from the tower computers on the basis of the design of the case as in tower computers .

21. Personal Computer (Desktop)

22. Personal (Micro) Computers : Uses
Laptop Computers
A laptop is a personal computer designed for mobile use.
It is small and light enough to sit on a person’s lap while in use.
A laptop integrate most of the typical components of a desktop computer , including a display , keyboard, a pointing device ( a touch pad, also known as a track pad, and / or a point stick, speakers, and often including a battery, into a single small and light unit.

23. Personal Computer (Laptop)

24. Personal (Micro) Computers : Uses
Palmtop Computers
A computer small enough to hold in one hand and operate with the other. Also called a “handtop”
These ultra-small computers may have specialized keyboards or keypads for data entry applications or have small qwerty keyboards.
Because of their small size, most palmtop computers do not include disk drives .
However, many contain PCMCIA(Personal Computer Memory Card International Association) slots in which you can insert disk drives, modems, memory, and other devices.

25. Personal Computer (palmtop)

26. Personal (Micro) Computers : Uses
Tablet Computers
A tablet personal computer (tablet PC) is a portable personal computer equipped with a touchscreen as a primary input device and designed to be operated and owned by an individual
The Tablet PC provides all of the features, reliability and power of Windows XP, plus pen and ink capabilities that allow you to write directly on the screen or use the pen as you would a mouse and keyboard.
The Tablet PC extends the way you would use a laptop or notebook computer.
You can use the wireless pen to take notes while in meetings, sketch ideas, even add personality to your and instant messages.

27. Tablet Computers, Google Glass & wearable Pc

29. 4mb Hard Disk
Core i7

30. Motherboard Ref: Prepared By : Muhammad Qasim Rafique
1. Computer Applications in Business (Dr Liaqat Ali Ch.)
2.www