HISTORY OF COMPUTERS

"Who invented the computer?" is not a question with a simple answer. The real answer is that many inventors contributed to the history of computers and that a computer is a complex piece of machinery made up of many parts, each of which can be considered a separate invention.


The earliest known device to record computations was the abacus. It dates back to ancient times and was invented by the Chinese. Ten beads were strung onto wires attached to a frame. Addition and subtraction were read from the final positions of the beads. It was considered the first manual tool used in calculating answers to problems that provided information and in a primitive way storing the results.

Mechanical Clock

During the Middle Ages the first closed system in terms of calculating information was invented by use of a mechanical clock. The parts of the clock calculated the time of day. The time was displayed through the position of two hands on its face. The inventor pre-programmed the clock instructions through the manner in which the pull of the weights and the swing of the pendulum with the movement of the gears established the position of the hands on the clock face.

Mathematics

John Napier (Scotsman mid 1600s) discovered logarithms. He devised a system where he put the logarithms on a set of ivory rods called "Napier’s Bones". By sliding the numbers up and down he invented a very primitive slide rule. Robert Bissaker perfected the system by placing numbers on sliding pieces of wood rather than ivory.

Blaise Pascal

(1642) developed the first real calculator. Addition and subtraction were carried out by using a series of very light rotating wheels. His system is still used today in car odometers which track a car’s mileage.

Gottfried van Leibnitz
(German mathematician) In 1690 Leibnitz developed a machine that could add, subtract, multiply, divide, and calculate square roots. The instructions were programmed into the machine. Programming was accomplished through the use of gears. The drawback to this machine was that the instructions could not be changed without changing the whole machine.

Joseph Jacquard

(early 1800’s) Jacquard developed a loom controlled by punched cards. The cards were made of cardboard which were programmed with instructions. Each card represented a loop, and the machine read the cards as they were passed over a series of rods. The loom was the early ancestor of the IBM punched card.

Charles Babbage

(1812) Babbage was a genius of a man who saw few of his inventions actually built. He designed and built a model of what was called the difference engine. This invention was designed to perform calculations without human intervention. The ultimate goal of the machine was to have the machine calculate logarithm tables and print the results. Babbage was so far ahead of the times that the technology was not in place to manufacture the parts for his machine so he was only able to build a small model. In 1833, Babbage then designed the analytic engine. This machine had many of the same parts that could be found in modern day computers. It had an arthmetic unit which performed calculations. Another part of the computer was called the "store" which stored intermediate and final results and instructions. This was completed for each stage of calculation. It was to get its instructions from punched cards and worked through mechanical means. The machine would be able to perform any calculation. Before the machine could be made Babbage died. His son built a small model of the work that still exists today. Babbage became known as the father of the modern day computers.

Dr. Herman Hollerith

(late 1800 statistician) Hollerith used the punched card method to process data gathered in the census. The previous census had taken seven years to complete because of the large amount of data collected that needed to be processed. By developing the Hollerith code and a series of machines which could store census data on cards, he was able to accomplish the accounting of the census in two and a half years with an additional two million pieces of data added. His code was able to sort the data according to the needs of the United States Government. He was known for developing the first computer card and accomplishing the largest data processing endeavor undertaken at the time. Hollerith set up the Tabulating Machine Company which manufactured and marketed punched cards and equipment to the railroads. The railroads used the equipment to tabulate freight schedules. In 1911, the Tabulating Machine Company merged with other companies to form the International Business Machine Corporation (IBM).

William Burroughs
(late 1890’s) designed the mechanical adding machine. The machine operated by way of a crank and was key driven. The Burroughs Adding Machine Company was to become one of the giants of the computer industry. His machine could record, calculate, and summarize. Today, Burroughs has merged with UNISYS which builds computers.

The Years from 1900-1940

During the next forty years, more of the adding, calculating, and tabulating machines were developed. Eventually the machines evolved to a point where they could multiply, interpret the alphabetic data, recordkeeping, and other accounting functions. They were called accounting machines.

Howard Aiken
(1944) The Mark I ,through a collaboration with Harvard University, IBM, and the U.S. War Department, was developed to handle a large amount of number crunching. The complex equation solving that was needed to map logistics in the military was the driving force behind this project. ( The United States was at war with Germany.) The Mark I was the first automatic calculator. It was not electronic, but did use electromagnetic relays with mechanical counters. It was said that when it ran the clicking sound was unbearable. Paper tape with hole punched in it provided the instruction sets, and the output was returned through holes punched in cards.

J. Presper Eckert and John W. Mauchly

(ENIAC, 1946 University of Pennsylvania) The ENIAC (Electronic Numerical Integrator and Calculator) was an electronic computer sponsored by the war department. It was classified because of war purposes. The ENIAC was so large that it took up a room ten feet high by about ten feet wide and several hundred feet in length. It could perform multiplication in the 3/1000 of a second range. There were 18,000 vacuum tubes in the machine and instructions had to be fed into the machine by way of switches because there was no internal memory within the machine.

Jon Von Neumann
(late 1940’s) devised a way to encode instructions and data in the same language. This paved the way for computer instructions to be stored in the computer itself. He was the forced behind the development of the first stored-program computer.

A Race Between the EDVAC and the EDSAC

Two groups of individuals were working at the same time to develop the first stored-program computer. In the United States, at the University of Pennsylvania the EDVAC (Electronic Discrete Variable Automatic Computer) was being worked on. In England at Cambridge, the EDSAC (Electronic Delay Storage Automatic Computer) was also being developed. The EDSAC won the race as the first stored-program computer beating the United States’ EDVAC by two months. The EDSAC performed computations in the three millisecond range. It performed arithmetic and logical operations without human intervention. The key to the success was in the stored instructions which it depended upon solely for its operation. This machine marked the beginning of the computer age.


The Major Milestones in Computer History