What is Computer
Computer is an advanced electronic device that takes raw data a s input from the user and processes these data under the control of set of instructions (called program) and gives the result (output) and saves output for the future use. It can process both numerical and non-numerical (arithmetic and logical) calculations.
A computer has four functions:
a. accepts data - Input
b. processes data - Processing
c. produces output- Output
d. stores results - Storage
Input is the raw information entered into a computer from the input devices. It is the collection of letters, numbers, images etc.
Process is the operation of data as per given instruction. It is totally internal process of the computer system.
Output is the processed data given by computer after data processing. Output is also called as Result. We can save these results in the storage devices for the future use.
Types of Computer
On the basis of Size
a) Super Computer
The fastest 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.
b) 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 supp ort more simultaneous programs. But supercomputers can execute a single program faster than a mainframe.
c) 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 simultaneous ly.
d) Micro Computer
i. Desktop Computer: a personal or micro-mini computer sufficient to fit on a desk.
ii. 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.
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."
The process of loading the system files of the operating system from the disk into the
computer memory to complete the circuitry requirement of the computer system is called
booting. The system files of MS. DOS are:
Types of Booting:
There are two types of booting:
• Cold Booting: If th e computer is i n off state and we boot the computer by pressing the power switch ‘ON’ from the CPU box then it is call ed as cold booting.
• Warm Booting: If the computer is a l ready ‘ON’ and we restart it by pressing the ‘RESET’ button from the CPU box or CTRL, ALT and DEL key simultaneously from the keyboard then it is called warm booting.
How to Shutdown (Turn Off) the Computer
Before shutting down the Computer, close all opened windows at first. Then,
1. Click on Start button.
2. Click on Shutdown (Turn Off Computer).
Then, Computer asks you to what do you want the Computer to do
• Shutdown (Turn Off)