but he also coined the phrase maze by trial-and-error means, [April 23]. of remembering the solution, and also of forgetting it in case April 30th In Sept. 1943, Stibitz finished the the situation changes and the Model II, one of the first solution is no longer applicable.” programmable calculators. The Hale’s Tours of the Model III was nicknamed “the baby” since its “fault” alarm World often went off during the night, April 30 – Dec. 1, waking people up. 1904 The Model V was the most ambitious, two of which were “Hale’s Tours of the World,” built in 1946 and 1947. Each one conceived by George C. Hale and contained over 9,000 relays, William Keefe, was an could store up to 30 7-digit amusement park attraction decimals, and took about a which might be considered the second to multiply two values earliest form of immersive real- together. Numbers were world simulation. represented in floating point, a feature absent from later digital A 15-minute tour took place in computers for many years, but an imitation railway passenger relatively easy to implement Claude Shannon. Photo by carriage which could with relays. Konrad Jacobs. CC BY-SA 2.0 de. accommodate around 50 people. Through the carriage’s windows, Stibitz began experimenting Shannon also published the first the passengers saw various with electrical gadgets while still paper on computer chess [Nov travelogues, rear-projected onto a boy. As usually happens in 8], and built several chess- screens. “Realism” was such cases, he nearly set his playing machines to test his increased by park staff rocking parent's house on fire by ideas, including one that moved the carriage, a wind machine, overloading its wiring with an the pieces with a three-fingered and sound effects. There was electric motor (given to him by arm. also a ‘conductor’, who snipped his father). tickets, and ‘lectured pleasantly’ Some of his other game-playing throughout the excursion. devices included one that solved the Towers of Hanoi problem, The first Hale’s Tours appeared Claude Elwood manipulated a Rubik’s Cube [Jan at the 1904 St. Louis Exhibition, 30], and Nimwit which played and hundreds of copies soon Shannon Nim expertly [Sept 24]. spread throughout the US and Canada. Born: April 30, 1916; His interest in building machines Petoskey, Michigan led him to develop the Minivac Died: Feb. 24, 2001 601 Digital Computer Kit [Oct 00], which became very popular Shannon is known as “the father George Robert in the early 1960's. Less serious of information theory”, a subject inventions included the he created with the landmark Stibitz THROBAC (Thrifty Roman- paper, “A Mathematical Theory Numeral Backward-Looking Born: April 30, 1904; of Communication” in 1948. He’s Computer), and the “Ultimate York, Pennsylvania also credited with founding Machine” based on an idea by Died: Jan. 31, 1995 digital circuit design theory, Marvin Minsky [Aug 9]. It with his Masters thesis [Aug 10] In 1937, Stibitz realized that consisted of a plain-looking box (1937) on the electrical boolean logic circuits could be with a switch on its side. When application of Boolean algebra; built from electromechanical the switch was flipped, the lid of its been called the most relays, and constructed the the box opened, a mechanical important Masters thesis of all Model K [Nov 00], a binary hand reached out, flipped off the time. In a spare moment in 1948, adder, to prove it. This switch, then retracted back Shannon coined the word “bit.” prototype persuaded Bell labs to inside the box. fund the creation of his Complex Shannon made several Shannon and his wife Betty used Number Calculator (CNC) [Jan important contributions to AI to enjoy weekend trips to Las 8], and several more relay through his interest in games Vegas with mathematician Ed calculators during the war, so and puzzles. For example, he Thorp [Aug 14]. To add to their the CNC was retroactively built a maze-solving mechanical fun, Shannon and Thorp renamed the Model I. mouse called “Theseus” as part invented a small, concealable of his work on telephone Not only is Stibitz one of the computer to help them calculate switching systems. He described fathers of the digital computing, odds while playing roulette. it as being “capable of solving a

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Outside of his academic pursuits, electrical impulses which Shannon crafted a series of operated relays controlling 11 Edward Yourdon unicycles, trying to see how motors. Some of them allowed Born: April 30, 1944; small they could be before they his fingers to bend, and a large USA became impossible to ride. He motor in his torso drove four Died: Jan. 20, 2016 invented a rocket-powered rubber rollers under each foot, Frisbee, motorized Pogo sticks, a enabling him to move. Another Yourdon was one of the mind-reading machine, several motor worked bellows so that developers of structured juggling machines, and a flame- Elektro could 'realistically' analysis techniques in the throwing trumpet. smoke a cigarette. 1970's, a co-developer of the Yourdon/Whitehead method for A quote: “I visualize a time when He could also speak about 700 object-oriented analysis and we will be to robots what dogs words, recorded as short design in the late 1980's, and the are to humans, and I’m rooting messsages on a 78-rpm record Coad/Yourdon methodology in for the machines.” player. the 1990's. Although Elektro appeared in During the late 1990's, he the same pavilion as Pedro the became widely known for his Voder [June 5] and the Nimatron Elektro and Sparko opinion that Y2K-related [Dec [Sept 24], he was the only robot, 31] problems might culminate in April 30, 1939 – Oct. (and so probably quite lonely). widespread societal collapse. 27, 1940 But in 1940, he was joined by Sparko the robot dog which The 1939-40 New York World’s could bark, wag its tail, sit up, Fair, displayed a number of and beg for a hot dog. Newsweek Robert Endre wonders that seem destined to magazine assured its readers be commonplace in “the world that it wouldn’t bite. Sparko was Tarjan of tomorrow”. designed by Don Lee Hadley, modelled after his Scotty dog. Born: April 30, 1948; "Elektro the Moto-man" was a Pomona, California seven-foot tall humanoid robot After WWII, Elektro toured the built by Joseph M. Barnett of US making promotional Tarjan is known for his work on Westinghouse Electric, covered appearances for Westinghouse, graph theory and data with an aluminum skin and and enjoyed a brief acting structures. Some of his weighing 265 pounds. career, appearing as “Thinko”, in algorithms include Tarjan’s “Sex Kittens Go to College” strongly connected components (1960). During the movie's algorithm (a stated favorite of dream sequence, Elektro turns Donald Knuth's [Jan 10]), and his rapidly, his eyes light his Hopcroft-Tarjan planarity up, and smoke billows from his test (can a graph be drawn neck, while burlesque dancers without crossing edges?), the perform around him. first linear-time algorithm of its type. Today he resides more quietly at the Mansfield Memorial His data structures include the Museum. There have been splay tree (a self-adjusting claims that Sparko's was run binary search tree; co-invented over in the 1950's when by Tarjan and Daniel Sleator), attracted to car lights, but this and the Fibonacci heap (a fast seems unlikely since his eyes priority queue involving a forest only lit up. of trees). These offer behind- the-scenes speedups to several For more robot men, see [Feb important problems. 00], [Feb 24], [March 23], [March 24], [April 16], [July 17], As a child, Tarjan became [July 30], [Sept 15], [Nov 11], interested in mathematics after [Nov 30], [Dec 22]. reading Martin Gardner’s [May Elektro and Sparko. 22] mathematical games For more electric/robot dogs, Photo by Daderot. columns in Scientific American. see [May 11], [June 7], [Sept 27], [Nov 18]. Internally, it consisted of a system of camshafts, gears and SIAM motors, which meant it was capable of performing 26 April 30, 1952 movements. These were linked to commands that its operator The Society for Industrial and spoke into a microphone. Each Applied Mathematics (SIAM) word was converted into was founded in 1951, but

2 became a non-profit same marbles and flip-flops would do little to promote the organization on this day. Rumor approach to create "Dr. NIM" MSN brand. has it that SIAM may also stand (1966), a ’computer' capable of Incidentally, ’s for “Science and Industry playing Nim. marketing slogan at the time Advance with Mathematics”. Although the name was very was “where do you want to go It has become the world’s suggestive, the Digi-Comp II today?” largest professional association wasn't programmable like the Unsurprisingly, the iLoo concept devoted to applied mathematics, Digi-Comp I [Sept 30] which wasn't new: Andrew Cubitt had with over 14,500 individual E.S.R. had released in 1963. prototyped an ’i-Loo" at Brunel members and over 500 University in 2001. institutional members. For more action, see [April Past presidents have included Web Made Public 16]. John Mauchly [Aug 30], J. Barkley Rosser, Gene H. Golub, April 30, 1993 Gilbert Strang, and Cleve Moler At the urging of Tim Berners-Lee [Aug 17]. [Dec 9] [June 8], the directors of CERN Sasser Worm was an early vice-president. [Sept 29] released the source SIAM is one of the digital trinity code of the WorldWideWeb [Dec Released of professional societies that 25] browser and its associated April 30, 2004 computing people tend to join, Web protocols into the public the others being the ACM [Sept domain. As a result, many The Sasser worm targeted 15] and IEEE [Jan 1]. historians mark this day as the Windows XP [Oct 25] and birth of the Web, although Windows 2000 by exploiting a others prefer [Dec 25] 1990, buffer overflow problem. It when the first Web page went spread by sending itself to Digi-Comp II live. randomly selected IP addresses. Patented This release came just two One of the interesting aspects of months after the announcement this attack was that a bug fix had April 30, 1965 that the server implementation been issued 17 days earlier, but there were still more than a The Digi-Comp II was a of the Gopher protocol [Feb 7] million infections recorded, mechanical device using marbles would no longer be free to use. costing an estimated $18 billion. and plastic flip-flop gates to That was enough to produce a For example, the British perform binary arithmetic. It rapid shift away from Gopher, coastguard lost access to its looked not unlike a pinball towards the Web. electronic mapping service for a machine, and was manufactured few hours. by E.S.R., Inc. A patent was filed for its design by John Thomas Microsoft iLoo On May 7, 2004, a 18-year-old Godfrey on this day, and granted German on July 2, 1968. April 30, 2003 student was arrested for writing the worm. Authorities were led The iLoo, supposedly being to him partly through developed by Microsoft’s MSN information obtained in division, was a response to a bounty [Nov 4] (aka a “loo” in the UK) equipped offered by Microsoft. with a wireless keyboard and a height-adjustable screen in front For more virus nasties, see [Jan of the seated user. MSN was also 26; March 26; May 5; July 13; reported to be in talks with July 15; July 17; Sept 5; Oct 26; toilet-paper manufacturers to Nov 21]. produce paper with interesting printed on the sheets. The principal use-case for the iLoo would be at events such as Inform 7 Released music festivals. April 30, 2006 On May 12, Microsoft announced Inform is a programming that the iLoo concept was a language developed by Graham “ perpetrated by its British Nelson for writing interactive division” calling it an April Fool’s A Digi-Comp II. fiction (IF) games, where the joke. On May 13, a second oldcomputermuseum.com. players use text commands to release clarified control their characters and this by stating that although the investigate the game It proved so popular that project had not been a hoax, it environment. Godfrey and E.S.R. later used the had been cancelled because it

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Notable language features include rule-based programming, and the ability to infer properties of objects from the way they are used in sentences. For example, the processing of the statement “John wears a hat.” creates a “person” called “John”, and a “hat” “thing” with the “wearable” property. This is done through the analysis of each sentence based on its grammatical elements, a feature that can be traced back to systems such as ELIZA [Jan 8] and SHRDLU [Feb 24]. Inform was created by Nelson in part to make it easier for hobbyists to create IF games that matched the same high standards as the Zork series [Dec 00] developed by Infocom [June 22]. Indeed, the first Inform compiler generated Z- code that was executed by a Z- machine, both of which were created at Infocom for Zork. Nelson styles himself as a mathematician and poet, and has been described by as “ornately literate.” The first IF game was Will Crowther’s Adventure [March 11].

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