A complete, working computer. Computer systems will include the computer along with any software and peripheral devices that are necessary to make the computer function. Every computer system, for example, requires an operating system.

The computer system has one or more inputs to provide data. This data is then processed in some way. The outcome of the processing is sent to an output or it may be stored until some event happens to cause it to be output.

For processing to take place, there needs to be a set of instructions of what needs to be done. This set of instructions is called a program.

This system is called a stored-program computer.

The very first commercial computer in the entire world of this type was built in Britain in 1949 and was called the Manchester (Ferranti) Mark 1, see below.

The beauty of this type of computer system is that it is flexible - the machine performs a different task by simply loading a different program from storage.


A motherboard is the physical arrangement in a computer that contains the computer's basic circuitry and components. On the typical motherboard, the circuitry is imprinted or affixed to the surface of a firm planar surface and usually manufactured in a single step. The most common motherboard design in desktop computers today is the AT, based on the IBM AT motherboard. A more recent motherboard specification, ATX, improves on the AT design. In both the AT and ATX designs, the computer components included in the motherboard are:
  • The microprocessor
  • (Optionally) coprocessors
  • Memory
  • basic input/output system (BIOS)
  • Expansion slot
  • Interconnecting circuitry


Although most moderately tech-savvy people today know that a CPU is one of the components in their computers, not many people know what a CPU actually does. In fact, if asked, most people probably would not know what CPU stands for.

But when searching for a new desktop or laptop, and typical CPU-related terms such as “quad-core” or ” i7 core” pop out from advertisements, each proclaiming their superiority over the other — what is a person to do, especially if he or she has no idea what either of those terms mean?First of all, what is a CPU? CPU (also commonly called a microprocessor) stands for “central processing unit”. It’s a very suitable name, because it describes exactly what the CPU does: it processes instructions that it gathers from decoding the code in programs and other such files. A CPU has four primary functions: fetch, decode, execute, and writeback.