computer

A computer is a programmable machine that receives input, stores and manipulates data, and provides output in a useful format.A general purpose computer has four main components: the Arithmetic Logic Unit (ALU), the control Unit, the memory, and the input and output devices. These parts are interconnected by buses, often made of groups of wires.Computer that is capable of performing just the simplest operations can be programmed to break down the more complex operations into simple steps that it can perform.
A computer have a memory which store data for future uses. A computer memory define into two principle  varieties: RAM [Random Access Memory] & ROM [Read Only Memory].But ROM is pre-loaded with data and software that never changes, so the CPU can only read from it. ROM is typically used to store the computer's initial start-up instructions.