Anuj Arora Email: anuja@uci.edu

1. Anuj AroraEmail: anuja@uci.edu

2. History of Inventors George Stibitz 1904-1995 Pioneer of digital computing and remote job entry

3. History Leading to an Idea • In 1927 an American scientist, engineer, and politician named Vanneyar Bush designed an analog computer that could solve simple equations. • In 1937, Claude Shannon, a student at Massachusetts Institute of Technology was working on his master’s thesis on Boolean algebra and electronic circuitry. • George Stibitz, while a researcher at Bell Labs, realized that Boolean logic could be used for the circuitry of electromechanical telephone relays.

4. Building on an Idea • Stibitz constructed his machine to solve a manpower problem at Bell Laboratories. The phone company had begun to rely on complex numbers in the equations that computed characteristics of filters and transmission lines. Thirty people worked full time at the impossible task of performing these computations on large, bulky desk calculators.   • Looking for a more efficient way to get the job done, Stibitz experimented at home with the concept of building a calculator that would automatically solve complex arithmetic problems with binary computations. • The most convenient parts available were the old-fashioned electromechanical telephone relays because they could be switched either on or off to represent 0s and 1s; the relays were ideal for performing binary calculations. • He started tinkering away with old relays, batteries, flashlight bulbs, wires and tin cans while at his kitchen table.

5. The Invention • The device, named the “Model K” (because it was constructed on his kitchen table) worked in the following sense: If two relays were activated they caused a third relay to become active, where the third relay is a sum of the operation. For example, if the two relays representing the number 3 and 6 were activated, this would activate another relay representing the number 9.

6. Refining the Invention • Satisfied that his concept would work, Stibitz convinced his boss to build a full-scale working model. • Bell Labs recognized this invention as a potential solution to the problem of high-speed complex-number calculation, which was holding back contemporary development of wide-area telephone networks. • By late 1938 the laboratory had authorized development of a full-scale relay calculator on the Stibitz model. • Stibitz and his design team began construction in April 1939. The end product, known as the Complex Number Calculator, first ran on January 8, 1940. • The result was the prototype binary adder circuit - an electromechanical circuit that controlled binary addition. Stibitz incorporated his new circuitry into his Model K • Stibitz took his circuit back to Bell Labs and over the next two years, working in conjunction with Samuel Williams, devised a machine that could calculate all four basic mathematical functions with complex numbers. • The Complex Number Calculator (later re-named the Bell Labs Model Relay Computer), came to be widely recognized as the world's first electronic digital computer.

7. Showing the World • In 1940, Stibitz performed a spectacular demonstration at a meeting in New Hampshire. Leaving his computer in New York City, he took a teleprinter to the meeting and proceeded to connect it to his computer via telephone. In the first example of remote computing, Stibitz astounded the attendees by allowing them to pose problems which were entered on the teleprinter; within a short time the teleprinter presented the answers generated by the answers generated by the computer.

8. The Device • The Model K went into operation, chopping off two-thirds of the time needed to solve the equations. The machine consisted of two large banks of telephone relays, each bank measuring eight feet in height, five feet across and a foot thick. Each relay was five inches long and one and a half inches wide. The left bank handled the complex values, while the right bank juggled the integer numbers. Then the two banks were integrated for the final solution. The fact that it held only 32 bytes of memory (1/32K), and that it cost a whopping $20,000 to build, took nothing away from its success. • Bell went on to build bigger and better versions of the relay-based computer, but this technology was dated almost as soon as it was assembled. Relay-based computers were more reliable than vacuum-tube-blowing behemoths like ENIAC, but the relays were outclassed in calculating speed by about 500 to 1.

9. Another Look At the Invention Complex ComputerDigital ComputerPatent Number 2,668,661 “The Keyboard of the Model One relay-based computer attests to its limited functions”

10. Impact of Invention • All of today's computers can trace their roots back to Stibitz' talent and imagination. • His binary computer, U.S. Patent No. 2,668,661 issued in 1939, now takes its place next to other great American inventions like the Model-T, the cotton gin, the electric light and the Wright brothers' plane. • A replica of this device is now on display at the Smithsonian Institution.

11. Timeline of Events • 1904 – Born on April 20 in York, Pennsylvania • (exact date unknown) - Attended Moraine Park, an experimental school in Dayton, Ohio • 1926 - Graduated from Denison University in Granville, OH with a Ph.D. in Applied Mathematics • 1927 - Graduated from Union College in Schenectady, NY receiving an M.S. • 1930 - Graduated from Cornell with a Ph.D. in Mathematical Physics • 1930 - Joined Bell Telephone Laboratories and served as a mathematical consultant • 1937 - Interest in computers arose from an assignment dealing with the study of magneto-mechanics of telephone relays • 1938 - With help, created the full-scale calculator for complex mathematics • 1939 - Entered the National Inventors Hall of Fame • 1940 - 1945 - Worked at the U.S. Office of Scientific Research and Development • (exact date unknown) - Following WWII he was an independent consultant in applied mathematics for various government and industrial agencies • 1964 - Joined the Department of Physiology at the Dartmouth Medical School as a research associate and worked on applications of physics, mathematics, and computers to biophysical systems • 1965 - Received the Harry Goode Award for a lifetime achievement in engineering from AFIPS • 1970 - Became a professor emeritus of physiology at the medical school of Dartmouth College • 1995 – After achieving 38 patents, he died on January 31 at his home in Hanover, NH at the age of 90