A step towards automated computing was the development of punched cards, which were first successfully used with computers in 1890 by Herman Hollerith (left) and James Powers, who worked for the US Census Bureau. They developed devices that could read the information that had been punched into the cards automatically, without human help. Because of this, reading errors were reduced dramatically, work flow increased, and, most importantly, stacks of punched cards could be used as easily accessible memory of almost unlimited size. Furthermore, different problems could be stored on different stacks of cards and accessed when needed.
These advantages were seen by commercial companies and soon led to the development of improved punch-card using computers created by International Business Machines (IBM), Remington, Burroughs, and other corporations. These computers used electromechanical devices in which electrical power provided mechanical motion – like turning the wheels of an adding machine. Such systems included features to: feed in a specified number of cards automatically, add, multiply, and sort feed out cards with punched results.
As compared to today’s machines, these computers were slow, usually processing 50 – 220 cards per minute, each card holding about 80 decimal numbers (characters). At the time, however, punched cards were a huge step forward. They provided a means of I/O, and memory storage on a huge scale. For more than 50 years after their first use, punched card machines did most of the world’s first business computing, and a considerable amount of the computing work in science.
Electronic Digital Computers
The start of World War II produced a large need for computer capacity, especially for the military. New weapons were made for which trajectory tables and other essential data were needed. In 1942 John P. Eckert, John W. Mauchly (left), and their associates at the Moore school of Electrical Engineering
of University of Pennsylvania decided to build a high – speed electronic computer to do the job. This machine became known as ENIAC (Electrical Numerical Integrator and Calculator).
The size of ENIAC’s numerical “word” was 10 decimal digits, and it could multiply two of these numbers at a rate of 300 per second, by finding the value of each product, from a multiplication table stored in its memory. ENIAC was therefore about 1,000 times faster then the previous generation of relay computers.
ENIAC used 18,000 vacuum tubes; about 1,800 square feet of floor space, and consumed about 180,000 watts of electrical power. It had punched card I/O, 1 multiplier, 1 divider/square rooter, and 20 adders using decimal ring counters, which served as adders and also as quick-access (.0002 seconds) read-write register storage. The executable instructions making up a program were embodied in the separate “units” of ENIAC, which were plugged together to form a “route” for the flow of information.
These connections had to be redone after each computation, together with presetting function tables and switches. This “wire your own” technique was inconvenient (for obvious reasons), and with only some latitude could ENIAC be considered programmable. It was, however, efficient in handling the particular programs for which it had been designed.
ENIAC is commonly accepted as the first successful high – speed electronic digital computer (EDC) and was used from 1946 to 1955. A controversy developed in 1971, however, over the patentability of ENIAC’s basic digital concepts, the claim being made that another physicist, John V.
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