Although the development of computers began with
the Abacus and other early mechanical calculating
devices, Charles Baggage is credited with the design
of the first modern day computer (the "analytical
engine") during the 1830s.
The American scientist Vannevar Bush built a mechanically
operated device, called the Differential Analyzer,
in 1930. It was the first general-purpose analog computer.
John Atanassoff constructed the very first semi electronic
digital computing device in 1939. The very first fully
automatic calculator was called the Mark I. Another
name for the Mark I is Automatic Sequence Calculator.
Howard Aiken created it at Harvard. While the ENIAC
(Electronic Calculator Integrator And Calculator),
which used thousands of Vacuum tubes, was completed
in 1946 at the University of Pennsylvania. The UNIVAC
(UNIVersal Automatic Computer 1951) soon became the
first computer to have the ability to handle numeric
and alphabetic data with the equal facility. The UNIVAC
then became the first commercial available computer.
Analog Computers:
An analog computer represents data as a physical
quantity and operates on the data and it manipulates
the quantities. The analog computer is designed to
process its data in which the variable quantities
vary continuously. Analog computers are really useful
in making simulations and evaluating dynamic situations;
such as the flight path of a space capsule or the
constantly changing weather over a certain area. The
most key component of the analog computer is it's
operational amplifier. The number of amplifiers (almost
always over 100) that the computer contains determines
the computer's capacity. Most analog computers are
found in the form of things such as speedometers and
watt-hour meters, they have been largely made obsolete
for general-purpose mathematical computations and
data storage by the new and improved Digital Computers
of today.
Digital Computers:
Digital computers are designed to process data in
numerical form; its circuits directly perform the
mathematical operations (addition, subtraction, multiplication,
and division). The numbers that are used by digital
computers are expressed in a system called Binary.
Binary digits, also know, as bits are simply the numbers
0 and1. The numbers 0,1,10,11,100,101, etc. correspond
to 0,1,2,3,4,5 etc. Binary digits are easily expressed
in the computer circuits by the presence (1) or absence
(0) of a current or voltage. When there is a series
of eight consecutive bits then this is called a byte,
the eight-bit byte can permit 256 different "on-off"
combinations. Each of these byte can represent up
to 256 alphanumeric characters.
Some languages, such as Japanese, Chinese, and Korean,
require more than 256 unique symbols. A digital computer
can store all the results of the calculations for
use in later operations that it performs.
Digital computers are used mostly for things such
as scientific investigations, data as well as word
processing programs, electronic games, and also for
such things as desktop publishing.
