There are many components inside the case of a computer. To control the components in the systems, there is a chip called the BIOS, or Basic Input Output System. It is the main way for all the parts of hardware to communicate with the motherboard. It also has a set up utility, which allows the user to configure the setting on how the BIOS and POST will function and what order they will work in.

The BIOS runs the POST, or Power On Self Test, which starts the boot process and tests the standard components. The POST makes sure that all the critical components, such as Random Access Memory, CPU, and video card, are all working properly when the computer is first turned on.

The BIOS stores a report of assigned addresses, for each piece of hardware.

The motherboard is the central board of the computer, where all the main connection ports are mounted. It is also called a mainboard. The motherboard houses the buses between the main components.

A bus is an electrical path on the motherboard, through which data is transmitted. The three primary buses are the system bus, the input / output bus, and the connection bus.

A chipset is the contolling center for the system bus and the bridge to the Input / Output bus.

The Central Processing Unit (CPU) in most of today's standard Pentium class systems have a chip that is about 3.5"x3.5"

The CPU handles the logical processes of the computer. The CPU is generally composed of a control unit, an Arithetic Logic Unit, and temporary data registers. The control unit sends the mathematical operations to the ALU, or Arithmetic Logic Unit. The CPU stores and retrieves data and instructions from the RAM.

RAM holds the data that the system is currently using, or has been using recently. RAM is often several chips mounted on a circuit board that is placed in sockets on the mainboard. There are many types of RAM today.

The next main component is the video card. It is usually placed in an expansion slot on the mainboard. It takes data pocessed by the computer and then sends them to the monitor for display.

On the mainboard, computers usually have controllers for parallel ports, serial ports, PS/2 port, floppy drives and hard drives.

The parallel ports are where external devices (such as printers, scanners, tape drives, etc.) can connect. A serial port can also be used to connect external devices, such as external modems or a serial mouse. The PS/2 port is a port for the PS/2 mouse.

With PCs, users can also get USB controllers. The USB controllers are for newer Pentium systems with TX chipset or higher. They allow one to add and to remove devices externally without shutting down. To get this, one needs a supporting OS, an operating system that has the drivers for the USB ports.

The floppy drive is a crucial component. In order to set up most hard drives and operating systems, you need one.

The hard drive controller tells the hard drive what to do. It transfers data to and from the I/O bus.

The mass storage, such as a hard drive, is where all the data is stored.