2. A device that performs high-speed mathematical or logical operations or that assembles, stores, correlates, and otherwise processes information.
3. Someone who utilizes a programmable electronic machine that has special procedures for accomplishing results: Computers can perform complex and repetitive procedures quickly, precisely, and reliably; as well as, quickly storing and retrieving large amounts of data.
The physical components from which a computer is constructed and which provide electronic circuits and input/output devices are known as "hardware".
Most computers have four types of hardware components: CPU, input, output, and memory.
The CPU, or central processing unit, executes programs known as "software" which direct the computer what to do.
Input and output, I/O, devices allow the computer to communicate with the user and the outside world.
There are several kinds of memory for computers that include fast, expensive, short term memory, known as RAM, to hold intermediate results, and slower, cheaper, long-term memory; such as, magnetic disk and magnetic tape, to hold programs and data between jobs.
Origin of the word computer
The term computer is a word which was formed in English from the verb compute and it has a recorded history going back to 1646, when it was used to mean "a person who computes".
In 1897, the word was first recorded as "a calculating machine", although that particular machine, which was "of the nature of a circular slide rule", did not resemble a modern computer.
Humans were the earliest computers. These "counting persons" were professionals who worked with numbers and were credited with great accuracy. The early computing was manual and involved the use of such counting tools as the abacus and a variety of slide rules.
When adding machines were developed, the man or woman who computed with one of these "rapid" devices, often called the counting machine a computer.
2. An apparatus that receives, processes, and presents information.
The two basic types of computers are analog and digital.
Although generally not regarded as such, the most prevalent computer is the simple mechanical analog computer, in which gears, levers, ratchets, and pawls perform mathematical operations; for example, the speedometer and the watt-hour meter (used to measure accumulated electrical usage).
The general public has become much more aware of the digital computer with the rapid proliferation of the hand-held calculator and a large variety of intelligent devices and especially with exposure to the Internet and the World Wide Web.
This is done automatically with an internally stored program of machine instructions.
Such instruments are distinguished from calculators on which the sequence of instructions is externally stored and is impressed manually (desk calculators) or from tape or cards (card-programmed calculators).