In this blog you will learn about:

  1.  Classifications of computers
  2.  Common types of computers today
  3.  Characteristic features of various types of computers in use today

Classifications of computers

  • Traditionally, computers were classified by their size, processing speed, and cost
  • Based on these factors, computers were classified as microcomputers, minicomputers, mainframes, and supercomputers
  • However, with rapidly changing technology, this classification is no more relevant
  • Today, computers are classified based on their mode of use

Types of computers

Based on their mode of use, computers are classified as:
  •  Notebook computers
  •  Personal computers
  •  Workstations
  •  Mainframe systems
  •  Supercomputers
  •  Clients and servers
  •  Handheld computers

Notebook Computers

  • Portable computers mainly meant for use by people who need computing resource wherever they go
  • Approximately of the size of an 8½ x 11 inch notebook and can easily fit inside a briefcase Weigh around 2 kg only.
  • Comfortably placed on ones lap while being used. Hence, they are also called laptop PC 
  • Lid with display screen is foldable in a manner that when not in use it can be folded to flush with keyboard to convert the system into notebook form
  • Designed to operate with chargeable batteries
  • Mostly used for word processing, spreadsheet computing, data entry, and power point presentations
  • Normally run MS-DOS or MS WINDOWS operating system
  • Some manufacturers are also offering models with GNU/Linux or its distributions
  • Each device of laptop is designed to use little power and remain suspended if not use.


Personal computers

  • Non-portable, general-purpose computer that fits on a normal size office table
  • Designed to meet personal computing needs of individuals
  • Often used by children and adults for education and entertainment also
  • Generally used by one person at a time, supports multitasking
  • Two common models of PCs are desktop model and tower model
  • Popular OS are MS-DOS, MS-Windows, Windows-NT, Linux, and UNIX


Workstations

  • Powerful desktop computer designed to meet the computing needs of engineers, architects, and other professionals
  • Provides greater processing power, larger storage, and better graphics display facility than PCs
  • Commonly used for computer-aided design, multimedia
  • applications, simulation of complex scientific and engineering problems, and visualization
  • Generally run the UNIX operating system or a variation of it
  • Operating system is generally designed to support multiuser environment


Mainframe system

  • Mainly used by large organizations as banks, insurance companies, hospitals, railways, etc.
  • Used for data handling and information processing requirements
  • Used in such environments where a large number of users need to share a common computing facility
  • Oriented to input/output-bound applications
  • Typically consist of a host computer, front-end computer, back-end computer, console terminals, magnetic disk drives, tape drives, magnetic tape library, user terminals, printers, and plotters
  • Typical mainframe system looks like a row of large file cabinets and needs a large room
  • Smaller configuration (slower host and subordinate computers, lesser storage space, and fewer user terminals) is often referred to as a minicomputer system

Supercomputers

  • Most powerful and most expensive computers available at a given time.
  • Primarily used for processing complex scientific applications that require enormous processing power.
  • Well known supercomputing applications include:
  1.  Analysis of large volumes of seismic data
  2. Simulation of airflow around an aircraft
  3. Crash simulation of the design of an automobile
  4. Solving complex structure engineering problems
  5. Weather forecasting
  • Supercomputers also support multiprogramming
  • Supercomputers primarily address processor-bound applications

Parallel processing system

  • § Use multiprocessing and parallel processing
  • technologies to solve complex problems faster
  • § Also known as parallel computers or parallel processing
  • systems
  • § Modern supercomputers employ hundreds of
  • processors and are also known as massively parallel
  • processors

 

Client and server computers

  • Client-server computing environment has multiple clients, one/more servers, and a network
  • Client is a PC/workstation with user-friendly interface running client processes that send service requests to the server
  • Server is generally a relatively large computer that
  • manages a shared resource and provides a set of
  • shared user services to the clients
  • Server runs the server process that services client requests for use of managed resources
  • Network may be a single LAN or WAN or an internet work

Client - Server Computing

  • Involves splitting an application into tasks and putting each task on computer where it can be handled most efficiently
  • Computers and operating systems of a client and a server may be different
  • Common for one server to use the services of another server, and hence act both as client and server
  • Concept of client and server computers is purely role-based and may change dynamically as the role of a computer changes 

Handheld Computers

  • Small computing device that can be used by holding in hand, also known as palmtop
  • Size, weight, and design are such that it can be used comfortably by holding in hand
  • Types of Handheld are:
  1. Tablet PC: Miniaturized laptop with light weight, screen flip, handwriting and voice recognition 
  2. PDA/Pocket PC: Acts as PIM device with LCD touch screen, pen for handwriting recognition, PC based synchronization, and optionally mobile phone services
  3. Smartphone: Fully functional mobile phone with computing power, voice centric, do not have a touch screen and are smaller than PDA