Sunday 5 August 2012

Computer Components


Computers come in all types and sizes. There are primarily two main sizes of computers. They are:
  • Portable
  • Desktop
The portable computer comes in various sizes and are referred to as laptops, notebooks, and hand-held computers. These generally denote different sizes, the laptop being the largest, and the hand-held is the smallest size. This document will mainly talk about the desktop computer although portable computer issues are also discussed in various areas.





Computer Components:

Computers are made of the following basic components:
  1. Case with hardware inside:

    1. Power Supply - The power supply comes with the case, but this component is mentioned separately since there are various types of power supplies. The one you should get depends on the requirements of your system. This will be discussed in more detail later
    2. Motherboard - This is where the core components of your computer reside which are listed below. Also the support cards for video, sound, networking and more are mounted into this board.

      1. Microprocessor - This is the brain of your computer. It performs commands and instructions and controls the operation of the computer.
      2. Memory - The RAM in your system is mounted on the motherboard. This is memory that must be powered on to retain its contents.
      3. Drive controllers - The drive controllers control the interface of your system to your hard drives. The controllers let your hard drives work by controlling their operation. On most systems, they are included on the motherboard, however you may add additional controllers for faster or other types of drives.

    3. Hard disk drive(s) - This is where your files are permanently stored on your computer. Also, normally, your operating system is installed here.
    4. CD-ROM drive(s) - This is normally a read only drive where files are permanently stored. There are now read/write CD-ROM drives that use special software to allow users to read from and write to these drives.
    5. Floppy drive(s) - A floppy is a small disk storage device that today typically has about 1.4 Megabytes of memory capacity.
    6. Other possible file storage devices include DVD devices, Tape backup devices, and some others.

  2. Monitor - This device which operates like a TV set lets the user see how the computer is responding to their commands.
  3. Keyboard - This is where the user enters text commands into the computer.
  4. Mouse - A point and click interface for entering commands which works well in graphical environments.

Computer of Classification


Computers differ based on their data processing abilities. They are classified according to purpose, data handling and functionality.
According to purpose, computers are either general purpose or specific purpose. General purpose computers are designed to perform a range of tasks.
They have the ability to store numerous programs, but lack in speed and efficiency. Specific purpose computers are designed to handle a specific problem or to perform a specific task. A set of instructions is built into the machine.
According to data handling, computers are analog, digital or hybrid. Analog computers work on the principle of measuring, in which the measurements obtained are translated into data. Modern analog computers usually employ electrical parameters, such as voltages, resistances or currents, to represent the quantities being manipulated. Such computers do not deal directly with the numbers. They measure continuous physical magnitudes. Digital computers are those that operate with information, numerical or otherwise, represented in a digital form. Such computers process data into a digital value (in 0s and 1s). They give the results with more accuracy and at a faster rate. Hybrid computers incorporate the measuring feature of an analog computer and counting feature of a digital computer. For computational purposes, these computers use analog components and for storage, digital memories are used.

According to functionality, computers are classified as :
Analog Computer 
 An analog computer (spelt analogue in British English) is a form of computer that uses continuous physical phenomena such as electrical, mechanical, or hydraulic quantities to model the problem being solved
Digital Computer
 A computer that performs calculations and logical operations with quantities represented as digits, usually in the binary number system
Hybrid Computer (Analog + Digital)
 A combination of computers those are capable of inputting and outputting in both digital and analog signals. A hybrid computer system setup offers a cost effective method of performing complex simulations.
 On the basis of Size
Super Computer
The fastest and most powerful type of computer Supercomputers are very expensive and are employed for specialized applications that require immense amounts of mathematical calculations. For example, weather forecasting requires a supercomputer. Other uses of supercomputers include animated graphics, fluid dynamic calculations, nuclear energy research, and petroleum exploration.
The chief difference between a supercomputer and a mainframe is that a supercomputer channels all its power into executing a few programs as fast as possible, whereas a mainframe uses its power to execute many programs concurrently.
Mainframe Computer
A very large and expensive computer capable of supporting hundreds, or even thousands, of users simultaneously. In the hierarchy that starts with a simple microprocessor (in watches, for example) at the bottom and moves to supercomputers at the top, mainframes are just below supercomputers. In some ways, mainframes are more powerful than supercomputers because they support more simultaneous programs. But supercomputers can execute a single program faster than a mainframe.
Mini Computer
A midsized computer. In size and power, minicomputers lie between workstations and mainframes. In the past decade, the distinction between large minicomputers and small mainframes has blurred, however, as has the distinction between small minicomputers and workstations. But in general, a minicomputer is a multiprocessing system capable of supporting from 4 to about 200 users simultaneously.
 Micro Computer or Personal Computer

 

Desktop Computer: a personal or micro-mini computer sufficient to fit on a desk.
Laptop Computer: a portable computer complete with an integrated screen and keyboard. It is generally smaller in size than a desktop computer and larger than a notebook computer.
Palmtop Computer/Digital Diary /Notebook /PDAs: a hand-sized computer. Palmtops have no keyboard but the screen serves both as an input and output device.
Workstations
A terminal or desktop computer in a network. In this context, workstation is just a generic term for a user's machine (client machine) in contrast to a "server" or "mainframe."


Computer History & Genarations


As the time passed, the device of more suitable and reliable machine was need which could perform our work more quickly. During this time, in the year 1946, the first successful electronic computer called ENIAC was developed and it was the starting point of the current generation of computer


First Generation of Computers
The first electronic computer was involved in the year 1946. Professors Eckert and Mauchly at the university of Pennsylvania in U.S.A led the team. This computer was called Electronic Numerical Integrator and Calculator  ENAIC. It used high-speed vacuum tube switching device




Second Generation of Computers





The second generation of computers appeared in 1955 and survived till 1965. These computers used transistors instead of vacuum tubes. During this period the magnetic cores were invented for storage. magnetic cores were used to develop large random access memories. Magnetic disk storage was also developed The higher reliability of computers and large memory availability led to the development of high level languages like FORTRAN COBOL Algol and Snobol.

Third Generation of Computers

In the generation of computers the germanium transistors were replaced by silicon Transistors The third generation began in the year 1965 and lasted till 1975. There were improvements in the design of magnetic core memories. The time Shared operation system increased the productivity of the programmers. In this generation the Integrated database management systems emerged and high level languages also improved.

Fourth Generation of Computers


First Phase (1976-85)

Medium Scale Integrated circuits resulted in large and Very Scale Integrated Circuits (VLSI). Magnetic core memories were replaced by semiconducting members. The introduction of microprocessor resulted in two directions in computer development. The emergence of the powerful personal computers was the first direction and the second direction. The emergence of the powerful personal computers was the first direction and second direction was decentralization of computer organization

Second Phase (1986-98)

In This phase the speed of the microprocessors increased more and also the size of the memory. The mainframe computer of early 80,s died in mid 90,s. Microprocessors like Pentium,Power PC, etc. are being used as the CPU.

Fifth Generation of Computers


This generation is based on Artificial Intelligence. The applications such as voice recognition are being used today. Due to parallel processing and superconductors, the artificial intelligence is becoming a success. In future quantum computation, molecular and nano technologies will change the look of the computers. the objective of the fifth generation computing is to develop devices that react to natural language input and are able to learn self-organize