Computer History

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Text of Computer History


2. The first computer were people.Computer was originally a job title it was used to describe those human beings (predominantly women) whose job it was toperform the repetitive calculationsrequired to compute such things asnavigational tables, tide charts, andplanetary positions for astronomicalalmanacs. 3. A typical computer operation back when computers were people. This picture shows what were known as "counting tables 4. The abacus was an early aid for mathematicalcomputations. Its only value is that it aids the memory ofthe human performing the calculation. . The abacus is oftenwrongly attributed to China. In fact, the oldest survivingabacus was used in 300 B.C. by the Babylonians. The abacusis still in use today, principally in the far east. 5. In 1617 an eccentric Scotsman named John Napier inventedlogarithms, which are a technology that allowsmultiplication to be performed via addition.The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. ButNapier also invented an alternative to tables , where the logarithm values were carved on ivorysticks which are now called Napiers Bones.An Original Napiers Bones 6. Napiers invention led directly to the slide rule, first builtin England in 1632 and still in use in the 1960s by theNASA engineers of the Mercury, Gemini, and Apolloprograms which landed men on the moon. 7. The first gear-driven calculating machineto actually be built was probablythe calculating clock, so named by itsinventor, the German professor WilhelmSchickard in 1623.This device got little publicity becauseSchickard died soon afterward in the bubonicplague. 8. In 1642 Blaise Pascal, at age 19,invented the Pascaline as an aidfor his father who was a taxcollector. Pascal built 50 of thisgear-driven one-functioncalculator (it could only add) butcouldnt sell many because of theirexorbitant cost and because theyreally werent that accurate (atthat time it was not possible tofabricate gears with the requiredprecision) . At the age of 12, he was discovered doing his version of Euclids thirty-second proposition on the kitchen floor. Pascal went on to invent probability theory, the hydraulic press, and the syringe. 9. Just a few years after Pascal, the German Gottfried Wilhelm Leibniz(co-inventor with Newton of calculus) managed to build a four-function (addition, subtraction, multiplication, and division) calculator that hecalled the stepped reckoner .Leibniz was the first to advocate use of the binary number system which is fundamental to the operation ofmodern computers. Leibniz is considered one of the greatest of thephilosophers but he died poor and alone. 10. In 1801 the Frenchman Joseph Marie Jacquard invented apower loom that could base its weave (and hence thedesign on the fabric) upon a pattern automatically readfrom punched wooden cards, held together in a long rowby rope. Descendents of these punched cards have beenin use ever since 11. By 1822 the English mathematician Charles Babbage wasproposing a steam driven calculating machine the size of aroom, which he called the Difference Engine. This machinewould be able to compute tables of numbers, such aslogarithm tables. Ten years later the device was still nowhere near complete, acrimony abounded between all involved, and funding dried up. The device was never finished. 12. The census bureau offered a prize for an inventor to helpwith the 1890 census and this prize was won by HermanHollerith, who proposed and then successfully adoptedJacquards punched cards for the purpose of computation.Holleriths invention, known as the Hollerith desk,consisted of a card reader which sensed the holes in thecards, a gear driven mechanism which could count(using Pascals mechanism which we still see in carodometers), and a large wall of dial indicators (a carspeedometer is a dial indicator) to display the results ofthe count. 13. IBM continued to develop mechanical calculators for saleto businesses to help with financial accounting and inventoryaccounting. One characteristic of both financial accountingand inventory accounting is that although you need tosubtract, you dont need negative numbers and you reallydont have to multiply since multiplication can be accomplished via repeated addition. 14. One of the four paper tape readers on the Harvard Mark I (you can observe the punched paper roll emerging from the bottom)One early success was the Harvard Mark I computer which was built as apartnership between Harvard and IBM in 1944. This was the first programmabledigital computer made in the U.S. But it was not a purely electronic computer.Heres a close-up of one of the Mark Is four paper tape readers. A paper tape wasan improvement over a box of punched cards as anyone who has ever dropped --and thus shuffled -- his "stack" knows. 15. One of the primary programmers for the Mark I wasa woman, Grace Hopper. Hopper found the firstcomputer "bug": a dead moth that had gotten intothe Mark I and whose wings were blocking the reading of the holes in the paper tape. The word"bug" had been used to describe a defect since least1889 but Hopper is credited with the word"debugging" to describe the work to eliminate program faults. 16. In 1953 Grace Hopper invented the first high-levellanguage, "Flow-matic". This language eventuallybecame COBOL which was the language most affectedby the infamous Y2K problem. A high-level language isdesigned to be more understandable by humans than isthe binary language understood by the computingmachinery. A high-level language is worthless without aprogram -- known as a compiler -- to translate it into thebinary language of the computer and hence GraceHopper also constructed the worlds first compiler.Grace remained active as a Rear Admiral in the NavyReserves until she was 79. The Mark I operated onnumbers that were 23 digits wide. It could add orsubtract two of these numbers in three-tenths of asecond, multiply them in four seconds, and divide themin ten seconds. 17. The microelectronics revolution is what allowed the amount of hand-crafted wiring seen in the priorphoto to be mass-produced as an integrated circuitwhich is a small sliver of silicon the size of yourthumbnail . The primary advantage of an integrated circuit is not that the transistors (switches) are miniscule (thats the secondary advantage), but rather that millions of transistors can be created and interconnected in a mass- production process 18. By the early 1980s this many transistors couldbe simultaneously fabricated on an integratedcircuit. Todays Pentium 4 microprocessor contains 42,000,000 transistors in this same thumbnail sized piece of silicon. Itshumorous to remember that in between the Stretch machine(which would be called amainframe today) and the Apple I acomputer)there was an entire industrysegment referred to as mini-computers such as the followingPDP-12 computer of 1969:The DECPDP-12 19. One of the earliest attempts to build an all-electronic (that is, no gears, cams,belts, shafts, etc.) digital computer occurred in 1937 by J. V. Atanasoff, aprofessor of physics and mathematics at Iowa State University. By 1941 he andhis graduate student, Clifford Berry, had succeeded in building a machine thatcould solve 29 simultaneous equations with 29 unknowns. This machine was thefirst to store data as a charge on a capacitor, which is how todays computersstore information in their main memory (DRAM or dynamic RAMThe Atanasoff-Berry Computer 20. Another candidate for granddaddy of the modern computer was Colossus, builtduring World War II by Britain for the purpose of breaking the cryptographic codesused by Germany. Britain led the world in designing and building electronicmachines dedicated to code breaking, and was routinely able to read codedGermany radio transmissions.The Harvard Mark I, the Atanasoff-Berry computer, and the BritishColossus all made importantcontributions. American and Britishcomputer pioneers were still arguingover who was first to do what, whenin 1965 the work of the German Konrad Zuse was published for thefirst time in English. Scooped! Zuse had built a sequence of general purpose computers in Nazi Germany. The first, the Z1, wasbuilt between 1936 and 1938 in the parlor of his parents home. 21. ENIAC which stood for Electronic Numerical Integrator and Calculator. ENIAC was built at University of Pennsylvania between 1943 and 1945 by two professors, John Mauchly and the 24 year old J. Presper EckertENIAC filled a 20 by 40 foot room, weighed 30 tons, and used more than18,000 vacuum tubes. Like the Mark I, ENIAC employed paper cardreaders obtained from IBM (these were a regular product for IBM, asthey were a long established part of business accounting machines,IBMs forte). When operating, the ENIAC was silent but you knew it wason as the 18,000 vacuum tubes each generated waste heat like a lightbulb and all this heat (174,000 watts of heat) meant that the computercould only be operated in a specially designed room with its own heavyduty air conditioning system. Only the left half of ENIAC is visible in thefirst picture, the right half was basically a mirror image of whats visible. 22. Even with 18,000 vacuum tubes, ENIAC could only hold 20 numbersat a time. However, thanks to the elimination of moving parts it ranmuch faster than the Mark I: a multiplication that required 6 secondson the Mark I could be performed on ENIAC in 2.8 thousandths of asecond. ENIACs basic clock speed was 100,000 cycles per second.Todays home computers employ clock speeds of 1,000,000,000cycles per second. Built with $500,000 from the U.S. Army, ENIACsfirst task was to compute whether or not it was possible to build ahydrogen bomb (the atomic bomb was completed during the war andhence is older than ENIAC). The very first problem run on ENIACrequired only 20 seconds and was checked against an answerobtained after forty h