When asked what a computer is, most people would describe a box on their desk at home. A computer can actually take a variety of shapes, sizes and forms. It is easiest to define a computer in terms of what it can do. A computer does the following four tasks:
1. A computer accepts input.
2. A computer processes the input in some way.
3. A computer produces output.
4. A computer stores data.
We will now explain each of these tasks in greater detail.
1. Accepting input
An input device (ex. keyboard, scanner, etc.) accepts input which is then relayed to the computer in the form of electronic signals. Input can take many forms ranging from words that a user had typed in to changing wind conditions detected by a doppler radar.
2. Processing input
Processing refers to the manipulation of data. Data is the representation of facts and ideas. An example of processing would be adding an area code to the front of a phone number, or addition of two numbers. Processing is done in the computer's CPU (central processing unit)
3. Producing output
Output is what the computer shows us, normally the result of some action that has just occured. Output is displayed using an output device (ex. monitor, printer, etc.).
4. Storage of data
Computers store data on some form of storage medium (ex. disks, CDs). This process allows the computer to use the data again without it having to be input over and over. It can also store the results of processing so that the processing does not have to be done over and over.
Categories of computers
Since there are so many different varieties of computers it is important to be able to sub-divide the idea of a computer into distinct categories. The computer categories are described below.
• Category: Mainframe
• Description: This was the first type of computer.
• Size: They are notoriously large, normally the size of a closet
• Price: Very expensive. Can easily exceed a million dollars.
• Location: They are most