Basic of Computer

What is a computer
A computer is, at its most basic, a machine which can take instructions, and perform computations based on those instructions.
Is the ability to take instructions and excecute them that differ a computer from a calculator.

Functions of Computers

1. INPUT- you input data i.e. you provide data; set of instuctions. You input data through input devices which are keyboard, mouse, scanner,etc
2. PROCESSING- the computer processes it i.e. it manipulates the data which is done by the C.P.U
3. OUTPUT- After processing the data the computer displays the result , it gives an output. Output devices are the monitor. Speakers, printers.

4. STORAGE- You can save your data for future use in the CPU itself which is stored in the computer's ROM. There are several other storage devices also like removeable disks , CDs, etc.

Characteristics of Computer

*Celerity(high speed)

*Authenticity(acurracy)

*Spontaneous(automatic)

*Pertinacy(endurance)

*Adaptability(versatile)

*Storehouse(memory)

*Cheaper(reduction of cost)

 Types of Computers

The types of computers range from the Hybrid to the Analog types. The computers you come across in the daily course of your day range from laptops, palmtops and towers, to desktop computers.

• Microcomputer: is a computer that has a microprocessor chip as its CPU. They are often called personal computers because they are designed to be used by one person at a time. Personal computers are typically used at home, at school, or at a business. they come in two major varieties; desktops and laptop computers. Desktop computers are larger and not meant to be portable. They usually sit in one place. The computer holds the motherboard, drives, power supply, and expansion cards.



• Workstation/Servers: is a powerful, high-end microcomputer. They contain one or more microprocessor CPUs. They may be used by a single-user for applications requiring more power than a typical PC. workstation-class microcomputers may be used as server computers that supply files to client computers over a network.



• Minicomputers: is a multi-user computer that is less powerful than a mainframe. This class of computers became available in the 1960’s when large scale integrated circuits made it possible to build a computer much cheaper than the then existing mainframes.

• Mainframes:  is a large, powerful computer that handles the processing for many users simultaneously (up to several hundred users). The name mainframe originated after minicomputers appeared in the 1960’s to distinguish the larger systems from the smaller minicomputers.
  
  Users connect to the mainframe using terminals and submit their tasks for processing by the mainframe. A terminal is a device that has a screen and keyboard for input and output, but it does not do its own processing (they are also called dumb terminals since they can’t process data on their own). The processing power of the mainframe is time-shared between all of the users.
• SuperComputers: is a mainframe computer that has been optimized for speed and processing power. The most famous series of supercomputers were designed by the company founded and named after Seymour Cray. The Cray-1 was built in the 1976 and installed at Los Alamos National Laboratory. Supercomputers are used for extremely calculation-intensive tasks such simulating nuclear bomb detonations, aerodynamic flows, and global weather patterns. A supercomputer typically costs several million dollars.

Personal computers come in two major varieties, desktop computers and laptop computers:
Desktop computers are larger and not meant to be portable. They usually sit in one place.