Early inventions• Used to mean humans who performed calculations• Abacus – 7 rings on rods, 2 for hands, 5 for fingers, that is used as an aid forcalculations; invented by Babylonians in 300 B.C.E.• Logarithms – Allows multiplication to be made by addition, by use of operands ona table; invented by Scotsman John Napier in 1617• Slide rule – Led directly from logarithms; invented by English in 1632, and used byNASA in the 1960’s• Calculating clock – Gear-driven calculating machine; invented by German professorWilhelm Schickard in 1623• Pascaline – A one-function calculator (adds), and same mechanism is used inodometers; invented by Blaise Pascal in 1642
Four-function calculators andpunched card• Stepped reckoner – A four-function calculator inventedby German Gottfried Wilhelm Leibniz a few years afterthe Pascaline; consisted of fluted drums having ten flutesarranged around their circumference in a stair-stepfashion (binary number system)• Punched cards - power loom that could base its weaveupon a pattern automatically read from punchedwooden cards, held together in a long row by rope;invented by Frenchman Joseph Marie Jacquard in 1801
Charles Babbage• Difference engine – Steam driven calculating machine proposed byBabbage, which would be able to compute tables of numbers;never finished• Analytic Engine – As large as a house and powered by 6 steamengines, and would be programmable because of punched cards• Innovations of the engine – Used to represent an abstract idea;used as a storage unit; had two parts, “Store” and “Mill”, which arenow “memory unit” and “central processing unit (CPU)”; had aconditional statement, which allows a program to achieve differentresults each time it is run
Herman Hollerith• Hollerith desk – Consisted of a card reader which sensed the holes in the cards, agear driven mechanism which could count, and a large wall of dial indicators (usedin speedometers) to display the results of the count; was used to help sped up thecensus; invented in 1890• Read/write – The punching (write) of new cards based upon an analysis (reading)of some other set of cards. Complicated analyses, too involved to be accomplishedduring a single pass thru the cards, could be accomplished via multiple passes thruthe cards using newly printed cards to remember the intermediate results.Different than read-only, when a tapestry was designed and then were notchanged.• IBM (International Business Machines) – Founded by Hollerith, and first calledTabulating Machine Company; made punch cards for things like bills, toll booths,ballots, and formerly Social Security and other checks
(Harvard) Mark 1• First programmable digital computer, as a partnership between Harvard and IBMin 1944• Constructed out of switches, relays, rotating shafts, and clutches. The machineweighed 5 tons, incorporated 500 miles of wire, was 8 feet tall and 51 feet long,and had a 50 ft. rotating shaft running its length, turned by a 5 horsepower electricmotor. The Mark I ran non-stop for 15 years, sounding like a roomful of ladiesknitting.• Shaft was the central power source; paper tape readers were an improvement tothe punched cards• Had the first computer “bug”, a dead moth whose wings were blocking the readingof the paper tape; also the first “debugging”• Inspired the high-level language “Flow-matic”, which is now COBOL, designed tobe understandable more to humans than computers; also inspired the compiler, aprogram to translate it into the binary language of the computer• Operated on numbers 23 digits wide, and add or subtract two numbers in 3/10 ofa second, multiply in 4 seconds, and divide in 10. Now can add in a billionth of asecond. Could store 72 numbers; RAM today can store 30 million numbers
After the Mark 1• Apple 1 – A home computer sold for $600; invented in 1976• CDC 7600 – Very expensive because of the tons of required hand assembly• Microelectronics revolution - Allowed a large amount of hand-craftedwiring to be mass-produced as an integrated circuit which is a small sliverof silicon the size of your thumbnail• Integrated circuit – The millions of transistors (switches) are miniscule andcan be created and interconnected in a mass-production process. All theelements on the integrated circuit are fabricated simultaneously by a smallnumber of optical masks that define the geometry of each layer, whichspeeds up the process of fabricating the computer and reduces its cost• IBM stretch – This computer possible because of the micro-electronicsrevolution; 33 feet long; had 150,000 transistors, and required individualassembly invented in 1959; today’s Pentium 4 microprocessor contains 42million transistors in same size silicon piece• The Stretch (mainframe) and Apple 1 (desktop computer) are mini-computers, like the PDP-12 computer invented in 1969
Back to World War 2• J.V. Atanasoff – Tried to build all electronic computer in 1937, but in 1941, heand Clifford Berry built a machine that could solve 29 equations with 29unknowns; it could store data as charge on a capacitor, used today in mainmemory (DRAM); first to use binary arithmetic; however, not programmableand no conditional branch• Colossus – Built during WWll by Britain to break the cryptographic codes usedby Germany; led the world in designing and building electronic machinesdedicated to code breaking, and was routinely able to read coded Germanyradio transmissions• Konrad Zuse – Built a sequence of general purpose computers in NaziGermany; the first, Z1, was built between 1936-38 in his parent’s home; thethird, Z3, built in 1941, was probably the first operational, general-purpose,programmable (that is, software controlled) digital computer; had anarithmetic unit to do the calculations, a memory for storing numbers, a controlsystem to supervise operations, and input and output devices to connect tothe external world; also the first high-level computer language, "Plankalkul"
The ENIAC• Built between 1943 and 1945 by two professors, John Mauchly and J. Presper Eckert• Filled a 20 by 40 foot room, weighed 30 tons, and used more than 18,000 vacuumtubes; employed paper card readers; was silent; the 18,000 vacuum tubes eachgenerated waste heat like a light bulb; all this heat (174,000 watts of heat) meant thatthe computer could only be operated in a specially designed room with its own heavyduty air conditioning system• To reprogram, had to rearrange the patch cords, and the settings of 3000 switches; toprogram a modern computer, you type out a program with statements like:• Circumference = 3.14 * diameter; to perform this computation on ENIAC you had torearrange a large number of patch cords and then locate three particular knobs on thatvast wall of knobs and set them to 3, 1, and 4.• A multiplication that required 6 seconds on the Mark I could be performed on ENIAC in2.8 thousandths of a second; ENIACs basic clock speed was 100,000 cycles per second,while today it is 1 billion cycles a second• John von Neumann helped design EDVAC, which pioneered the stored program.; theprogram (sequence of computation steps) could be represented electronically just asthe data was.
After the ENIAC• General protection fault/blue screen of death- modifications happen as fast ascomputers compute, and could modify themselves as they ran; faulty logic in programcould cause it to damage itself• Reprogramming – Allows it to do a wide variety of events, including special effects,music download, car tire rotation techniques, and writing style of Shakespeare’s work• UNIVAC – First commercial computer, built in the 50’s; means “Universal AutomaticComputer”; first to employ magnetic tape• IBM became dominant company; “IBM and the seven dwarfs”; hired Microsoft toprovide software for personal computer (PC); by 2000 their market capitalization wastwice IBM; mainframe computers came in 70’s, like IBM 7090, IBM 360, IBM 370• Time share - Giving the user a tiny sliver of time in round fashion, with up to 100 userlogged in, typing on a teletype, which is a motorized typewriter that could transmitkeystrokes to mainframe and print response on paper (type single text line, hit carriagereturn, and wait for it to print);• Binary numbers (0-1); easy to control, sense, make; either hole is punched or not;vacuum tubes replaced by transistors• Batch mode processing – Full attention to programming; have to run it off-line on a keypunch machine which generates punch cards; university students bought blank cards;one card holds one program statement, and submitted program by stackiing cards
1990’s to Present• In the 90’s, a university student would usually own his own computer andhave exclusive use of it in dorm room• Microprocessor (uP) – A computer that is fabricated on an integratedcircuit (IC); first developed at Intel in 1971; put an entire computer on achip; made a general purpose chip which could be reprogrammed fordifferent tasks• Program - A sequence of instructions stored in memory• Intel – Made the Intel 4004, the first uP, which had 2300 transistors andhas speed of 108 kHz; was on the Pioneer 10 spacecraft; then made 8008and 8080 (the 8080 was employed in MITS Altair, the first PC); Pentium 4has 42 million transistors and clock rate of 2 GHz• Busicom – Made a desk calculator, but went out of business• Bill Gates – Created Microsoft; dropped out of college, at same time IBMstandardized Intel uP for line of PCs in 1981; Pentium 4 is still compatiblewith 8088
Effects of computers onsociety, science, and technology• Everybody uses a computer for countless reasons,whether for info, games, videos, communication, work,or for any other reason.• They are important for science, to analyze data, docomplicated calculations, and research the topics.(Helps eliminate human error)• It is almost all technology, whether an I-pad, I-pod, X-box, TV, PSP, Reader, car, or a regular computer orlaptop. The are used in all space missions now, andespecially for things to dangerous for a human to do.Robots are possible because of computers.