Wednesday 5 July 2017

History of Computers

This chapter is a brief summary of the history of Computers. It is supplemented by the two PBS documentaries video tapes "Inventing the Future" And "The Paperback Computer". The chapter highlights some of the advances to look for in the documentaries.
In particular, when viewing the movies you should look for two things:
  • The progression in hardware representation of a bit of data:
    1. Vacuum Tubes (the 1950s) - one bit on the size of a thumb;
    2. Transistors (the 1950s and 1960s) - one bit on the size of a fingernail;
    3. Integrated Circuits (the 1960s and 70s) - thousands of bits on the size of a hand
    4. Silicon computer chips (the 1970s and on) - millions of bits on the size of a fingernail.
  • The progression of the ease of use of computers:
    1. Almost impossible to use except by very patient geniuses (the 1950s);
    2. Programmable by highly trained people only (the 1960s and 1970s);
    3. Useable by just about anyone (the 1980s and on).
to see how computers got smaller, cheaper, and easier to use.

First Computers

The first substantial computer was the giant ENIAC machine by John W. Mauchly and J. Presper Eckert at the University of Pennsylvania. ENIAC (Electrical Numerical Integrator and Calculator) used a word of 10 decimal digits instead of binary ones like previous automated calculators/computers. ENIAC was also the first machine to use more than 2,000 vacuum tubes, using nearly 18,000 vacuum tubes. Storage of all those vacuum tubes and the machinery required to keep the cool took up over 167 square meters (1800 square feet) of floor space. Nonetheless, it had punched-card input and output and arithmetically had 1 multiplier, 1 divider-square rooter, and 20 adders employing decimal "ring counters," which served as adders and also as quick-access (0.0002 seconds) read-write register storage.
The executable instructions composing a program were embodied in the separate units of ENIAC, which were plugged together to form a route through the machine for the flow of computations. These connections had to be redone for each different problem, together with presetting function tables and switches. This "wire-your-own" instruction technique was inconvenient, and only with some license could ENIAC be considered programmable; it was, however, efficient in handling the particular programs for which it had been designed. ENIAC is generally acknowledged to be the first successful high-speed electronic digital computer (EDC) and was productively 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 U.S. physicist, John V. Atanasoff, had already used the same ideas in a simpler vacuum-tube device he built in the 1930s while at Iowa State College. In 1973, the court found in favor of the company using Atanasoff claim and Atanasoff received the acclaim he rightly deserved.

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