The four basic functions of a computer are input, processing, output and storage. Input is the information which is entered into the computer. Processing is performing operations on or manipulating data. Output is the result of the data processing. Storage refers to devices that can retain the data when the computer is deactivated.
The first computers to use input, processing, output and storage included the Jacquard loom and Charles Babbage's Analytical Engine. The first electronic computers to use these four functions included the ENIAC, the UNIVAC and the Harvard Mark 1. The IBM 5150, which was introduced in 1981, also used all four functions.
Input devices on a modern computer include the keyboard, mouse and disk drives. The central processing unit (CPU) does processes the data. Devices such as read only memory (ROM), the hard drive, compact disks (CDs) and digital versatile disks (DVDs) can store the data. Output devices include the monitor, speakers, printer and rewritable CD and DVD disk drives.
When you input information into your computer with the mouse or keyboard, you're sending a signal to the CPU. The CPU has a logic unit that can do basic arithmetic. The control unit directs the computer to execute programs that have been stored in memory. The speed by which a computer executes programs is measured in millions of instructions per second (MIPS); the processor's speed is measured in gigahertz (GHz). When the information has been processed, it is output in a human-readable form through the monitor and speakers. It can also be stored again for later processing. Storage media can be used to both input and output data.
The four basic functions of a computer make it possible for us to perform many tasks that were previously impossible. Using a computer, you can balance your checkbook, purchase merchandise, send and receive messages, do research, process your photographs, create music and store crucial data, among other things. If you have essential computer skills you can find better employment for higher pay. Because computers are easily networked, they can help people from remote parts of the world communicate more quickly and easily than with traditional methods.
Computers can be addictive. Computer gaming, in particular, can cause people to abandon taking care of essential responsibilities. Working long hours at a computer can contribute to eye strain, repetitive strain injury (RSI) and lower back pain. Many people may forget to eat or exercise when on a computer for long periods. Using ergonomic devices and furniture and taking frequent breaks can help to prevent many of these computer-related health issues (see Resources below).