Basic Elements of a Computer System

A computer system is an interconnected system of components that transmit electronic information between them to accomplish a task given to the computer. Computer systems require several critical components to function, all of equal importance. The hardware components of the computer are the parts you can see and touch. The software components consist of electronic data and programs that give the hardware directions for functioning properly.

A keyboard is one example of a computer peripheral device.


The motherboard of a computer provides a pathway along which information and power can travel between components. The hard drive, power supply, other disc drives, processor and RAM all communicate using the motherboard. Motherboards typically have several expansion slots to connect peripheral devices.


The processor is the brain of the computer. It interprets input from the user, sends it to the computer as electronic signals and translates the signals into user-readable output. For example, typing a letter on a keyboard sends a signal to the processor. The processor then reinterprets the keyboard press as an electrical signal to send to a word processing program and to the monitor, alerting the monitor to display the corresponding characters.


RAM (random-access memory) provides the computer with memory to temporarily store instructions and data to be accessed by your processor. According to the Indiana University Knowledge Base, most computers made after 2002 use DDR2 (double data rate) RAM. This type of RAM transfers data more quickly without reducing your computer's overall performance. Different types of RAM, such as DDR2 and DDR3, cannot be used in the same computer.

Storage Media

RAM keeps data in short-term memory — the duration of the current work session. When you power off the computer, all data in RAM is lost. Storage devices, such as hard-disk drives or optical drives, allow you to store data long term for later access. Hard-disk drives have several platters that store data magnetically. When you access a file, the operating system looks for the location of the data on the hard drive and sends a signal to the actuator arm, which contains a needle that skims over and reads the clusters of magnetic charges that represent data. Optical drives use a laser that reflects off the read surface of a CD or DVD to represent data.


Peripheral devices connect to the computer externally. Your keyboard, mouse, monitor and speakers are all peripheral devices. The keyboard and mouse are input devices, allowing you to enter text or manipulate an on-screen cursor. The monitor is an output device. It interprets signals from your video card and displays an arrangement of pixels in different colors: red, green and blue. Your speakers interpret data coming from your soundcard and play it as MP3s or other audio files.