Introduction to Programming/Components of a computer

Central Processing Unit
At the heart of a computer is the Central Processing Unit (CPU) which performs the logical and arithmetical operations on streams of numbers as controlled by a “program” which is itself a stream of numbers. The CPU has access to the computer memory which the computer uses to hold numbers. The CPU can also send and receive numbers from input and output devices.

Random Access Memory
The Random Access Memory (RAM) is the memory where the computer holds information that is currently using. The memory behaves a bit like a series of numbered boxes, each of which can hold a number which can be stored or later retrieved by the CPU. Note that when the computer power supply is switched off, the contents of the RAM becomes lost.

Read Only Memory
Computers contain a Read Only Memory (ROM) chip that retains its information when the computer power supply is switched off. The Read Only Memory chip contains the BIOS program that enables the computer to startup and load other programs.

Devices and Peripherals
Devices are things that are part of the computer or attached to it, and are used for input or output, storage or communications, such as the disk drives, network cards, video cards, etc.

Peripherals are devices that are externally connected to the computer, such as the keyboard, display, printer, mouse or joystick.