A Brief History of Computers Bernard John Poole University of Pittsburgh

From Counting on fingers to pebbles to hash marks on walls to hash marks on bone to hash marks in sand Pre-Mechanical Computing: From Counting on fingers to pebbles to hash marks on walls to hash marks on bone to hash marks in sand Interesting thought: Do any species, other than homo sapiens, count?

Mechanical computers From The Abacus c BCE to Charles Babbage and his Difference Engine (1812)

Mechanical computers: The Abacus (c BCE)

Napier’s Bones and Logarithms (1617) Picture courtesy IBM

Oughtred’s (1621) and Schickard‘s (1623] slide rule

Blaise Pascal’s Pascaline (1645)

Gottfried Wilhelm von Leibnitz’s Stepped Reckoner (1674)

Joseph-Marie Jacquard and his punched card controlled looms (1804)

Charles Babbage ( ) The Father of Computers Inventor: cowcatcher, standard railroad gauge, dynamometer, uniform postal rates, occulting lights for lighthouses, Greenwich time signals, heliograph opthalmoscope.

Charles Babbage’s Difference Engine

Charles Babbage’s Analytical Engine

Lady Augusta Ada Countess of Lovelace Lady Augusta Ada Countess of Lovelace Lady Augusta Ada Countess of Lovelace Lady Augusta Ada Countess of Lovelace - Documented Babbage’s discoveries - programmed his machines

Electro-mechanical computers From Herman Hollerith’s 1890 Census Counting Machine to Howard Aiken and the Harvard Mark I (1944)

Herman Hollerith and his Census Tabulating Machine (1884)

A closer look at the Census Tabulating Machine

The Harvard Mark I (1944) aka IBM’s Automatic Sequence Controlled Calculator (ASCC) Howard AikenPhysics at Harvard Howard Aiken Physics at Harvard supported by IBM supported by IBM mechanical relays (switches) 35 tons with 500 miles of wiring

The first computer bug Rear Admiral Dr. Grace Murray Hopper

Electronic digital computers From John Vincent Atanasoff’s 1939 Atanasoff-Berry Computer (ABC) to the present day

Alan Turing Alan Turing Alan Turing Alan Turing The Turing Machine Aka The Universal Machine 1936

John Vincent Atanasoff ( ) John Vincent Atanasoff ( ) John Vincent Atanasoff ( ) John Vincent Atanasoff ( ) Physics Prof At Iowa State University 1937: idea of the first modern computer

Clifford Berry ( ) Clifford Berry ( ) Clifford Berry ( ) Clifford Berry ( ) PhD student of Dr. Atanasoff’s 1939: paper documenting their design

1939 The Atanasoff-Berry Computer (ABC) The ABC was the first electronic digital computer, invented by John Vincent Atanasoff

1943 Bletchley Park’s Colossus The Enigma Machine

1946 The ENIAC John Presper Eckert ( ) and John Mauchly ( ) of the University of Pennsylvania Moore School of Engineering

The ENIAC: Electronic Numerical Integrator and Computer 30 tons vacuum tubes

Programming the ENIAC programming = rewiring

ENIAC’s Wiring! John Von Neumann came up with the bright idea of using part of the computer’s internal memory (called Primary Memory) to “store” the program inside the computer and have the computer go get the instructions from its own memory, just as we do with our human brain. John Von Neumann

1951 Univac Typical 1968 prices—excluding maintenance & support!

Vacuum Tubes (1941 – 1956) First Generation Electronic Computers  ABC and ENIAC used Vacuum Tubes, invented by Lee de Forrest in 1907  Vacuum tubes are glass tubes with circuits inside.  Vacuum tubes have no air inside of them, which protects the circuitry.

Transistors ( ) Second Generation Computers  Uses Silicon  developed in 1948 by William Shockley and his team at Bell Labs (Nobel prize)  on-off switch  Speed, in electronic terms, is essentially a function of space. The transistor was a fraction the size of a vacuum tube and thus enabled significant advances in computing speed.

Integrated Circuits ( )  Third Generation Computers used Integrated Circuits (chips).  Integrated Circuits are transistors, resistors, and capacitors integrated together into a single “chip”

Very Large Scale Integrated Circuit (VLSI), 1971-today  Kilby and Noyce, who founded Intel Corporation, invented the semiconductor in They are the equivalent of a transistor, but layered onto a thin sliver of silicon using photomasking techniques  INTEL 4004 Microprocessor (by Hoff) 2,250 transistors four-bit chunks (four 1’s or 0’s) 108Khz Called “Microchip”

Personal Computers (1) MITS Altair  256 byte memory  2 MHz Intel 8080 chips  Just a box with flashing lights  cost $395 kit, $495 assembled

PCs (2) IBM PC – 1981  IBM-Intel-Microsoft joint venture  First wide-selling personal computer used in business  8088 Microchip - 29,000 transistors 4.77 Mhz processing speed  256 K RAM standard  One or two floppy disk drives

PCs (3) Apple II released 1977 widely used in schools Macintosh (left) released in 1984, Motorola Microchip processor first commercial computer with graphical user interface (GUI) and pointing device (mouse)

Summary: Evolution of modern computers