The Basic Structure of a Computer

Open computer showing CPU and hard disk

Virtually all computers, from home desktop machines to giant research systems, all share a basic structure. They have a central processor that computes and performs logic, memory that holds data, and input-output devices.

Central Processor

A computer's central processing unit (CPU) is its active "brain." It performs arithmetic, compares data, and moves data to and from the other parts.

Memory

High-speed random-access memory (RAM) is the CPU's "scratch pad." The CPU carries out programs loaded in RAM and manipulates data stored in RAM.

Buses

Most computers have several pathways to move data from RAM to the CPU and other parts. These paths are called buses and they move hundreds of millions of data characters per second.

Input/Output

Keyboards, mice, displays and printers are all types of input/output (I/O) devices. Data flows from keyboards and mice through the buses and into the CPU and RAM. Results of calculations flow back to the display and printer.

Hard Disk

A hard disk drive (HDD) is the computer's long-term "filing cabinet." It stores all your files and programs.

References

• WatchingTheNet.com: Computer Terms Explained
• ComputerMemoryUpgrade.net: How Computer RAM Works
• TechTerms.com: Bus Definition