computer
A computer is programmable machine . The two principal characteristics of a computer are : it responds to a specific set of instructions in a well defined manner and it can execute a prerecorded list of instructions .
Modern computer defined
Modern computers are electronic and digital . the actual machinery wires, transistor , and circuits is called hardware ; the instructions and data are called software .
all general purpose computers require the following hardware components:
- Memory : enables a computer to store , at least temporarily , data and programs
- mass storage device : allows a computer to permanently retain large amounts of data. common mass storage device include disk drivers and tape drives .
- input device : usually a keyboard and mouse , the input device is the conduit through which data and instructions enter a computer .
- Output device : a display screen , printer or other device that lets you see what the computer has accomplished .
- Central processing unit (CPU) : the heart of the computer , this is the component that actually executes instructions .
in addition to these components many others make it possible for the basic components to work together efficiently. For example , every computer requires a bus that transmits data from one part of the computer to another .
