Introduction to Prolog and Computational Linguistics -- An Extremely Brief History of Computing

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An Extremely Brief History of Computing

The Abacus

The construction (or attempted construction) of machines which manipulate data, in particular machines that count, is not a recent phenomenon--it is something that For instance an abacus partially conforms to the definition of computing above. This is how an abacus is used:

First, you select an initial position of the beads (representing the input data).
The beads are then manipulated with a finite number of operations (the algorithm).
The final position of the beads represent the output data.

The abacus certainly performs the data storage and access part of the definition of computing above, but the algorithm is both remembered and executed by the human. So an abacus is not strictly a computer.

The First Computers

The first machines which remembered and executed algorithms by themselves were based on the technology of gears. Input and output data was represented by the position of the gears, and the machine would step through a sequence of altering the positions of the gears. There were several machines of this type. One forerunner of modern computers was the mechanical weaving loom. Joseph Jaquard developed a technique by which the steps to be executed while weaving a pattern was encoded by holes in a paper card.

The machines that are usually considered to be the ancestors of computers are the mechanical calculating machines. There were several of these, but the Difference Engine built by Charles Babbage (1792--1871) is considered the first one to contain components corresponding to what is found in modern computers. The Difference Engine had the following properties:

Whereas the earlier machines could only execute set algorithms, the Difference Engine allowed the user to make up their own selecting from a set of steps. Hence, using it actually involved writing a program.
Input to a program is communicated to the machine by feeding in a piece of paper with holes on which was read in and used to set the initial position of the gears (as opposed to physically setting them).
Output from a program was printed on a piece of paper (on the earlier calculating machines it was determined from the position of the gears).

Babbage was working with Ada Lovelace (1815--1852), a mathematician. History credits the machine to him, though in all likelihood it was a collaborative project. As a consolation prize, perhaps, Lovelace is credited with writing the first program (you can find out more about their story and see different versions of the machine in the Science Museum in London).

The first electrical and electronic computers were built in the 1940s.

<a.von.klopp@bangor.ac.uk>