History of Digital Technology
Extract from the book 'Digital Technology'
Digital Computations
The term digital refers to the computation of numbers using a digit or finger and comes from the Latin worddigitus meaning finger.
The ten digits on our hands were the first means by which humans carried out calculations for trade and bartering. As trading routes expanded and larger volumes of goods were traded more efficient means of counting were needed.
The earliest known device to perform calculations such as addition and subtraction was the abacus. It performed arithmetic computations faster and easier than counting on the hand. It gave a greater flexibility for large numbers and an easier method for addition, subtraction, multiplication and division. It can be said that the abacus was the original computer and in a sense it was a digital device.
Traders, clerks and merchants throughout history have used the abacus for calculating prices and quantities of goods. Abacuses come in different shapes, forms and size. The earliest ones were simple devices using grooves in sand with beans or stones as digits counters. Later devices fashioned grooves in tablets made from wood, metal or stone and various materials for the counting digits. More modern devices were constructed of a frame with beads that slid on wires.
Mathematical computations such as addition, subtract, multiplication and division were carried out by moving the stones or sliding beads from one column to another
The word ‘computer’ was first used in 1613 to refer to a person who carried out calculations or computations such as navigational tables, tide charts, and planetary positions for astronomical almanacs. The word was used in such reference until about the middle of the 20thcentury when machines were built to do these calculations.
The first programmable analogue computer was invented in 1206 by Al-Jazari (1136 – 1206). He was a prominent Arab inventor, mechanical engineer and artist.
He designed a computer that displayed the zodiac, solar and lunar orbits and crescents of the moon. It also opened and shut doors every hour with mechanical musicians playing music when struck by levers. The significance of his computer was that it could be re-programmed to compensate for the changes in the length of day and night throughout the year.
In 1801, Joseph Marie Jacquard invented a mechanical loom that had holes punched in pasteboard with each row corresponding to one row of the textile’s design. A number of cards with multiple holes defined the design of the textile. This was an important step in computers because it conceptualised, and was later adopted, the notion of reprogramming electronic devices by using punched cards.
Charles Baggage was the first to design a fully programmable mechanical computer in 1837. His design was based on varying sizes of gears and although he did not build his machine, his ideas paved the way for future programmable computer design.
Herman Hollerith was the first to invent a machine that recorded data on punch cards. Information was recorded on punch cards using keypunch machines and processed through another one of his inventions called the Tabulator
Hollerith’s company, later to become IBM, performed the correlation of census data for the 1890 United States Census.
Extract from the book 'Digital Technology'