Categories of Computer

Categories of Computer

              Normally, computers are categorized on the basis of size, speed, processing power and price. However, categorizing computers is not very straight-forward. The distinction between these categories is sometimes not very clear. Some characteristics overlap different categories. Computers can be divided into the following categories:

1 Personal Computers / Micro Computers

             Personal computer is a type of computer that performs input, output, processing and storage activities by itself. It was introduced in 1970. It contains a processor, memory and one or more input, output and storage devices. It generally has one processor. However, some personal computers may have multiple processors. It is designed to be used by one person at a time. Most commonly used personal computers are PC and Apple Macintosh. The price of personal computer is from $500 to $5000.

                  Personal computers have different processors and operating system. PC and its compatible computers use windows operating system. Apple Macintosh and compatible computers use Macintosh operating system also called MAC OS.

          Pc and its compatible computers follow the specifications of the original IBM personal computer. Some PC compatible computers include Compaq, Dell and Toshiba. Following are different types of personal computers:

1.1 Desktop Computers

Desktop computers are the most common type of personal computer. It is designed in a way that all its components fit on a desk or a table and monitor is placed on system unit. In another model, called tower model, both monitor and system unit are placed on the table. The system unit in tower model is placed vertically.

          Different desktop computers are as follows:

·         All-in-One computer: It is less expensive computer. In this computer, monitor and system unit are combined into single device.

·         Workstation Computer:  It was introduced in early 1980s. It is more expensive and powerful personal computer. It is used for calculations and graphics work. A workstation can tackle task that require a lot of processing speed. It is mostly used by engineers, graphics artists and architects. Architecture uses a workstation to view and create maps. A graphics artist uses a workstation to create computer-animate special effects for full-length motion picture and video games.

·          Server computer: It is a computer that manages the resources of a network. It controls access to the software, hardware of the network. It also provides centralized area to store date, information and software.

1.1.2 Notebook Computers

Notebook computer is also called laptop computer. Laptop computer is small in size and can be placed easily on lap. Only one user can use them at a time. It uses less power. It can be used using batteries. A laptop computer can perform the same basic functions as a personal computer. The computing power of modern notebook computers are nearly equivalent to personal computers.

                A notebook computer contains CPU, memory capacity and disk drives. The keyboard and touchpad in notebook computer are placed on the top of system unit.

          Notebook computers can be brought anywhere easily because of lightweight. Its weight is generally around 2KG. They are easy to carry and can be used outdoors in airports and in classrooms without the need for nearby electrical outlet. Laptop computers are more expensive than desktop computers. The cost of these computers is from $1000 to $2500.

.11.3 Tablet PC

Tablet PC was introduced in 2002. It is a special type of notebook that works with digital pen. The user gives instructions with digital pen. It can also use keyboard for input. It also supports voice input. Many Tablet PCs have built-in microphone. Tablet PC is used to take notes in lectures, meetings, conferences etc. The price of tablet PC is high and it typically costs $2000 to $2500. Two basic design of Tablet PC are as follows:

·         Slate Tablet PC: In this Tablet PC, all the hardware is behind the display like PDA. The user can attach a removable kayboard to it. The storage devices, CPU and RAM are integrated into the screen. The Fujitsu ST4000 is a slate tablet PC.

·         Convertible Pc: The display on convertible Tablet PC is attached to a keyboard. It can be rotated 180 degrees and folded down over the keyboard. The convertible Tablet PC can be repositioned to look like a notebook computer. Toshibe s Portege 3500 is a convertible Tablet Pc.  

     2. Handheld Computers

     Handheld computer is also known as palmtop computer. It easily fits in the hand of the user. It contains small screen and small keyboard. Handheld often use stylus as input device to enter data. Some handheld computers also support voice input.

                         Handheld computers usually have no disk drive. The programs and data are stored on chips in the system unit. Handheld computer can be connected to a large network to exchange date. Handheld computer is not powerful enough to handle many of the tasks that can be accomplished be desktop and notebook computer.

            Some examples of handheld computers are as follows: 
          2.1 Personal Digital Assistant (PDA)

 

A PDA has touch-sensitive screens that is used to enter data directly with a penlike device called a stylus. Some PDAs include integrated keyboards or support small, portable, folding keyboards. PDAs also support voice input.

            PDA is used to organize personal information. It provides the facilities of calendar, appointment book, address book, calculator and notepad. PDAs also provide word processing, spreadsheet software and games. Most PDAs are web-enabled so the users can check email and access Internet.

            The user can also transfer data from PDA to desktop be using a device called cradle. It connects PDA to desktop using USB or serial port. The two main operating system for PDA are Palm OS and Windows Mobile system.

          Popular PDA processors include Motorola DragonBaH, Taxes Instruments OMAP and Intel Xscale processor. Palm Computing,Casio and Compaq are three of the most popular PDA manufacturers.

1.2.2 Smart Phone

                   Smart phone offers advanced feature that are not typically found in cellular phones. It provides the fecility to send and recive email and access the Internt. Some costly smart phones have color screens and can play music. They include built-in camera to share photographs or vedio with others. It is also called web-enabled cellular telephone.

3 Different between Desktop and Portable Computer:

The difference between desktop and portable computer are as follows:
CLICK on Image  To Enlrage

 

4 Internet Appliances:

Internet appliance is also known as information appliance. It is a computer that is used to connect to the Internet from home. It contains all software applications required to connect to the Internet and browse. Set-top box is one of the most popular Internet appliances. It is used to access the Internet and browse websites using a device similar to a remote control. It is connected to the television set to view web pages. 

5 Mini Computers :

Mini computer is larger and more powerful computer than personal computer. It can execute five million indtructuions per second. It generally consists of two or more processors. It is more reliable than desktop computer but not as solid as mainfram. Mini computers were introduced in 1960s. Mini computers are also called mid-range servers. These computers are more costly than micro computers. 

       Mini computer can serve up  to several hundreds connected computers simultaneously. It is normally accessed by users via personal computer or terminal. A device with a monitor ans keyboard is called terminal. It is also known  as dumb terminal. It has no processing power and cannot work as stand-alone computer. It has to be connected to a server.

Examples

       Examples of midrange servers are:

·         Prime 9755

·         VAX 8650

·         IBM System 360

·         AS 400

·         HP 3000

Uses of Mini Computers

           Mini computers are often used by small and medium-sized companies or departments to provide centralized store of information and computer programs.
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6 Mainframe Computers

            A mainframe computer is a large computer in terms of price, power ans speed. It was introduced in 1975. It is more powerful  than mini computer. It consists of multiple processor. It os specially designed to perform multiple tasks for multiple users simultaneously. It is designed for high reliability. It often runs twenty four hours a day. It can be serviced and upgraded while it is running. It is also known as enterprise server or high-ended server.

         Mainframe computers can servse several thousands users simultaneously. These computers can store large amounts of date, information and instruction. The users access a mainframe computer through terminal or personal computer. 

              The price of mainframe computer is normally several thousand dollars and can be up  to $5 million. IBM, Sun and Unisys are leading manufactures of mainframe computers.

Examples

     Examples of mainframe computers are as follows:

·         IBM43810

·         NEC 610

·         DEC 10 etc.

Uses of Mainframe Computers

              Mainframe computers are used in large organizations such as banks, educational institutions ans government departments etc. For example, airlines use these computers to maintain flight schedules, ticket reservation system etc. Govt departments such as NADRA use mainframe computers to maintain the information of population. Many shopping chains interconnect their stores with mainframe computer to track transactions immediately and maintain stock.

 

7 Super Comptuers  

          Super computer is a state-of-the-art machine. It was first developed id early 1970s. It is the biggest in size and the most expensive in price than any other computers. It is used to perform complex tasks. It has a very large storage capacity. It also consumes so much energy. It can process trillions of instructions in one second.

         The modern super  computer consists of thousands of microprocessors. An example of a super computer is ASCI white. It contains 8192 CPU and can perform 12 trillion calcuation per second. The cost of one super computer can be up to several million dollars.

Examples

       Examples of super computers are as follows:

·         CRAY-XP

·         ETA-10

·         Deep Blue

·         Blue Sky

Uses of Super Computers

         Super computer is mostly used for weather predictions, weapon design and atomic research etc. Super computer is also used in business and industry field. Aircraft manufactures use it to simulate aircraft and check it performance. Governments use super computer for different calculations ans heavy jobs. Many Hollywood movies use it for animation purposes.

8 Microcontrollers

             Microcontrollers are tiny and specialized microprocessors inside appliances and automobiles. They are also called embedded computer. They  are used in microwaves, programmable ovens, blood-pressure monitors, air bag sensors, vibration sensors, MP3 players, digital cameras, e-pliances, keyborads and car engine controllers etc. 

9 Different among Micro, Mini & Mainframe computers

          The difference between desktop and portable computer are as follows:
CLICK on Image  To Enlrage