Technically, a computer is a
programmable machine. This means it can execute a programmed list of
instructions and respond to new instructions that it is given.
Today, however, the term is most often used to refer to the desktop
and laptop computers that most people use. When referring to a
desktop model, the term "computer" technically only refers to the
computer itself -- not the monitor, keyboard, and mouse. Still, it
is acceptable to refer to everything together as the computer. If
you want to be really technical, the box that holds the computer is
called the "system unit."
Some of the major parts of a personal computer (or PC) include the
motherboard, CPU, memory (or RAM), hard drive, and video card. While
personal computers are by far the most common type of computers
today, there are several other types of computers. For example, a
"minicomputer" is a powerful computer that can support many users at
once. A "mainframe" is a large, high-powered computer that can
perform billions of calculations from multiple sources at one time.
Finally, a "supercomputer" is a machine that can process billions of
instructions a second and is used to calculate extremely complex