Classification/Types of Computer:
1) On the base of basic types
a) Analog Computer
o It is measure Physical value.
o It is measuring System.
o It handles the continuous physical Quantities
o Powerful in solving different equations.
o Use OP-AMP( operational amplifier ).
o Example: Temperature, Pressure, speedometer, thermometer.
2) Digital Computer
o It is counting system.(non-continuous).
o It handles the discrete logical quantities or signals.
o Accuracy is higher than analog computer due to precision value.
o Used for business and general application.
3) Hybrid Computer
o Combination of both analog and digital computer.
o The hybrid computer can transfer data from analog to digital to analog.
o Used for hospital, Jet plane, Industrial process controls.
2) On the Basic of size
a) Super Computer
o The fastest computer of the world.
o It is specially designed for massive parallel processing
o The speed of super computer is measure in FLOPS.
o FLOPS- Floating point operation per second
o Number crunching in super computer(It is also called the number cruncher)
o It performs complex numerical calculations.
o Number crunchers- The machines designed to perform numerical calculations at the highest speed.
o Used in intensive numerical analysis, weather forecasting, nuclear energy research, dynamic calculation, satellite communication (operation on space).
b) Mainframe computer
o Mainframe computer are very huge, very large and bulky computer.
o Mainframe computer system
o It is server/cabinet computer
o It has capabilities to support large number of terminals(thousands of)
o Generally used in centralized databases.
o It has input and output device only
o Uses in Transaction processing, Real time processing, Batch processing and
Management information system.
o The user access the mainframe computer via a terminal that may be a dumb terminal an intelligent terminal.
c) Minicomputer
o Minicomputer is digital computers, generally used in multi-user systems.
o Minicomputer can support 4-200 users simultaneously.(Hundred of terminal support)
o They are used for real time applications in industries, research centers, etc.
o The users can access the minicomputer through their PCs or terminal.
o PDA 11, IBM 8000 series are some of the widely used minicomputer.
d) Microcomputer
o Smallest type of computer, least expensive of all type.
o Known as personal computer
o Introduced by IBM.
o Low cost of development
o Arithmetic and control unite combined
o Uses by single person for single activity
o The first firm to mass market a microcomputer as a personal computer was RadioShack.
o The world's first laptop computer introduced in the market by Epson, 1981.
o Micro-computer is based in five categories :
Workstation, Desktop, Server, Laptop, Notebook
i) Desktop/Personal computer
Used by business for word processing, spread sheeting & Physically Placed on desk.
It is stand-alone machine that can be placed on the desk.
It is not very expensive and is suited to the needs of single user at home, small business units, and organizations.
ii) Notebook computer or Laptop
They are portable and have all the features of a desktop computer.
The advantages of Laptop is that it is small in size can be put inside the briefcase, it can be carried anywhere, it has a battery backup and has all the functionality of the desktop.
Laptops are costlier than the desktop machines.
iii) Tablet computer
It has the features of the notebook but it can accept input from a stylus or a pen instead of the keyboard or mouse, it is a portable computer. Tablet computer are the new kind of PCs.
iv) Handheld Computer or Personal Digital Assistant (PDA)
It is small computer that can be held on the top of the palm.
Casio and Apple are some of the manufactures of PDA.
vi) Smart Phone
It is cellular phones that function both as a phone and as a small PC.
Workstation:
o Higher processing speed than lowest category computer
o It provides- greater processing power, Better graphic display, and larger storage capacity.
o Used for- Computer Aid design, Multimedia application, simulation and visualization.
o Usually use UNIX based multiuser operating system.
Dumb Terminal:
It is used only for data entry and storage and never for processing.
It has Keyboard and Screen.
3) On the basic of brand
a) IBM PC
IBM PC is a microcomputer produced by IBM Company. Dr.Herman Horierith established IBM in 1923.
It is the leading the market of mainframe and PC’s.
IBM American Company called big blue.
Its old name is Computing Tabulating Recording Company.
b) IBM Compatible
IBM compatible can use hardware and software designed for IBM PC. The internal architecture of IBM compatible is
similar to IBM PC. So they are called duplicate computers.
Example Epson, Acer etc.
c) Apple/Macintosh
Apple Corporation was established in 1970 in USA.
The internal architecture of these computers is totally different form that of IBM.
Therefore they need their own software.
4) On the basic of model
a) XT computer
It is extra technology computer.
It is old technology computers with much slower processing speed.
Not more than 4.77 MHZ speed.
It used 4 bits processor length.
b) AT computer
Advance technology computer are the new technology computers.
They are faster processing.
More than 2 GHZ.
Word length exceeds 64 bits.
c) PS2 computer
It is refinement of AT computers.
These models were built after 1990’s and mostly used in Laptop computer.
Rechargeable and battery operational systems with faster flexible I/O devices are some important characterizes of these computer.