Computers work through an electronic switching system and we understand the switching system as binary code. Binary code is 1's and 0's, the 1's represent an on state in the computer and the 0 represent an off state. A single digit, either a 1 or 0, is a Bit. A sequence of 8 bits makes a Byte. With 8 bits to a byte, there are 256 combinations of 1's and 0's or 256 bytes that can be made. Each byte represents a Character or control Characters, which the computer can use for controlling the Central Processing Unit (CPU) or producing numbers and characters on the screen, printer or some other output device. A Program is a combination of thousands of these bytes controlling the computers CPU to perform a particular task, such as word processing, number crunching, games, Aircraft control, and etc. There are different types of output devices used in a computer system, printers, monitors, etc. Magnetic media (Magnetic disks, Magnetic tape) is also another form of output that is used as a storage device which stores the bits in a magnetic format. Then there is also CD's for storage. These same storage devices can be used to retrieve information for processing by the CPU. Input devices are keyboards, keypads, lightpens, laser scanners, etc. The most common one used in stores are keypads and laser scanners. And the output device used mostly is monitors, storage devices, and the cash register printer that prints out your receipt.

A laser is an instrument used to form a beam of optical radiation (Light) at a specified wavelength. The atoms of the gas inside the laser tube (such as hydrogen, deuterium, carbon dioxide, or fluorine depending on the type of laser) is excited by the laser lamp to a high energy level as they absorb their character wavelength from the white light. As the atoms de-excite, they emit their characteristic wavelength, and that wavelength only. This can occur either spontaneously or by encountering the emission of another atom. The reflective inner walls of the laser tube reflect these light waves back into the tube and toward other atoms, causing them to emit light also.

Some of the light waves are allowed to leave the tube, in this case through a semitransparent portion of the mirror and an opening in the tube wall. These waves emerge as a coherent beam of light, a laser beam. The beam is aligned as a result of reflections back and forth between the reflecting mirror at the left and the semitransparent mirror on the right. A Maser is the same thing as a laser but instead of optical wave forms being transmitted, a maser transmits microwave wave forms.