June 22, 2024

Intel and the Microprocessor


Pre-History, Charles Babbage

19th century mathematician and inventor of calculating machines.

"The Analytical Engine was conceived as a general-purpose device, capable of performing arithmetic or logical functions (whereas the Difference Engine was effectively a special-purpose calculator). Instructions were to be entered into the Analytical Engine by punch cards (as they were later for the first mainframe computers) and kept in a store, the equivalent of today's computer memory. Importantly Babbage foresaw the need to differentiate between the instructions given to the machine (the program) and the numbers entered into it (the data)."

Alan Turing

Work on Collossus and artificial intelligence. Turing test, a human operator has to try to tell the difference between a computer and another human being on the basis of replies received to typed queries. If the user cannot tell the difference, the computer can be said to possess intelligence.

John von Neumann

ENIAC (Electronic Numerical Integrator and Computer) project based at the University of Pennsylvania. ENIAC was the first large-scale computer, and was conceived by John Mauchly and Presper Eckert. ENIAC used vacuum tubes instead of the electromechanical relays used in other computing devices. The vacuum tubes performed the same function that transistors do in a modern microprocessor, that is they they could switch their state, being either on or off. Vacuum tubes were considerably faster than electromechanical relays (which were effectively physical switches which either closed or opened according to the electrical current), and thus ENIAC was capable of performing complex calculations, of the sort required for ballistics during the war, much more quickly than any other method.


Data processing computer, precursor of mainframes, developed by Mauchly and Eckert in a start-up. Success and publicity for the machine in the USA.


Monitors the success of computers and moves into mainframe development and dominates the market into the 70s.


The microprocessor is a form of integrated circuit, possessing millions of switches (transistors), but one that can be programmed. In other words, by setting the switches within the chip in a certain manner a microprocessor can be told to perform in a particular way. It has 3 main functions:

  1. It reads and writes to the RAM. The computer's memory contains the instructions and data to be used. This is the first task of the chip.
  2. To next is to use the data and so the chip must have its own set of instructions.
  3. Finally the microprocessor has to communicate with other parts of the computer. It acts as a coordinator.

Assembly Language

Programming language used to write machine code (1s and 0s); the basic instructions to the microprocessor. Assembly language translates instructions into machine code. Higher level languages (BASIC) were developed to hide this complexity.

There are 2 main functions of these basic instructions.

  1. Arithmetic. + - * / enables computers to carry out vast number of functions.
  2. Logic. AND, OR, IF, THEN and ELSE. Testing conditions.

The more transistors present in the chip the more functions it can perform. This function is then said to be "hard-wired" into the computer, and it can be performed very quickly.

Moore's Law

The number of transistors that can be placed on the same area of a microprocessor doubles every eighteen months. Price stays the same and power doubles. 2 implications for this:

  1. Computers become increasingly more powerful and therefore capable of more sophisticated tasks.
  2. Chips become cheaper. Older type chips drop in price and are then placed in other appliances. VTRs, washing machines etc.

Implications of Moore's Law

Cost of data storage also drops and means that it is increasingly easier, quicker and cheaper to process and store large amounts of data.

Microcontrollers used as control devices in array of machines and devices.

Social implications. More and more data is being processed. Credit checks, health records, data control and access to the data affects our lives.

Financial implications as prices drop. Replacing old machines becomes cheaper with increased functionality. Compare this with other industries eg cars. Computer industry is very different.


Founded by Bob Noyce and Gordon Moore. See Cringely Ch. 3

Ted Hoff, inventor of the microprocessor. Used Intel's planar process to put a general purpose circuit onto silicon thus avoiding hard wiring separate transistors in a particular way to perform a given task. The chip could now be programmed to perform specific tasks thus giving the chip flexibility of use. This would also have the advantage of cutting costs. Taking 9 months to develop and released in 1971 it was called the 4004.

Frederico Faggin, producer of the microprocessor and developer of the technology.

After the 4004

Intel had to sell the chip, no market existed. It needed to persuade electronics companies to find uses for it and had to convince programmers (of mainframes) to write software for it.

The next chip, the 8080 was the turning point, and the uptake of the 8086 by IBM was the key to Intel's success.


Fairchild/Intel produced the template for start-ups and their links with venture capitalists. High tech high risk and, if successful, high profit. Employees have stake in company via share options; highly motivated with lure of share in these profits causes them to work long hours with risk of burn-out. Silicon Valley has large number of skilled engineers and programmers to move around companies. If a start up fails, they can quickly find other work.


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