History of computers

History of Computers and its effects

Jeremy Hart

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 for

calculations; invented by Babylonians in 300 B.C.E.• Logarithms – Allows multiplication to be made by addition, by use of operands on

a table; invented by Scotsman John Napier in 1617• Slide rule – Led directly from logarithms; invented by English in 1632, and used by

NASA in the 1960’s• Calculating clock – Gear-driven calculating machine; invented by German professor

Wilhelm Schickard in 1623• Pascaline – A one-function calculator (adds), and same mechanism is used in

odometers; invented by Blaise Pascal in 1642

Four-function calculators and punched card

• Stepped reckoner – A four-function calculator invented by German Gottfried Wilhelm Leibniz a few years after the Pascaline; consisted of fluted drums having ten flutes arranged around their circumference in a stair-step fashion (binary number system)

• Punched cards - power loom that could base its weave upon a pattern automatically read from punched wooden 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 by

Babbage, which would be able to compute tables of numbers; never finished

• Analytic Engine – As large as a house and powered by 6 steam engines, 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 are now “memory unit” and “central processing unit (CPU)”; had a conditional statement, which allows a program to achieve different results each time it is run

Herman Hollerith• Hollerith desk – Consisted of a card reader which sensed the holes in the cards, a

gear driven mechanism which could count, and a large wall of dial indicators (used in speedometers) to display the results of the count; was used to help sped up the census; 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 accomplished during a single pass thru the cards, could be accomplished via multiple passes thru the cards using newly printed cards to remember the intermediate results. Different than read-only, when a tapestry was designed and then were not changed.

• IBM (International Business Machines) – Founded by Hollerith, and first called Tabulating 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 IBM in 1944• Constructed out of switches, relays, rotating shafts, and clutches. The machine weighed

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 electric motor. The Mark I ran non-stop for 15 years, sounding like a roomful of ladies knitting.

• Shaft was the central power source; paper tape readers were an improvement to the punched cards

• Had the first computer “bug”, a dead moth whose wings were blocking the reading of the paper tape; also the first “debugging”

• Inspired the high-level language “Flow-matic”, which is now COBOL, designed to be understandable more to humans than computers; also inspired the compiler, a program 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 of a second, multiply in 4 seconds, and divide in 10. Now can add in a billionth of a second. 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-crafted wiring to be

mass-produced as an integrated circuit which is a small sliver of silicon the size of your thumbnail

• Integrated circuit – The millions of transistors (switches) are miniscule and can be created and interconnected in a mass-production process. All the elements on the integrated circuit are fabricated simultaneously by a small number of optical masks that define the geometry of each layer, which speeds up the process of fabricating the computer and reduces its cost

• IBM stretch – This computer possible because of the micro-electronics revolution; 33 feet long; had 150,000 transistors, and required individual assembly invented in 1959; today’s Pentium 4 microprocessor contains 42 million 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, he and

Clifford Berry built a machine that could solve 29 equations with 29 unknowns; it could store data as charge on a capacitor, used today in main memory (DRAM); first to use binary arithmetic; however, not programmable and no conditional branch

• Colossus – Built during WWll by Britain to break the cryptographic codes used by Germany; led the world in designing and building electronic machines dedicated to code breaking, and was routinely able to read coded Germany radio transmissions

• Konrad Zuse – Built a sequence of general purpose computers in Nazi Germany; the first, Z1, was built between 1936-38 in his parent’s home; the third, Z3, built in 1941, was probably the first operational, general-purpose, programmable (that is, software controlled) digital computer; had an arithmetic unit to do the calculations, a memory for storing numbers, a control system to supervise operations, and input and output devices to connect to the 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 vacuum tubes;

employed paper card readers; was silent; the 18,000 vacuum tubes each generated waste heat like a light bulb; all this heat (174,000 watts of heat) meant that the computer could only be operated in a specially designed room with its own heavy duty air conditioning system

• To reprogram, had to rearrange the patch cords, and the settings of 3000 switches; to program a modern computer, you type out a program with statements like:

• Circumference = 3.14 * diameter; to perform this computation on ENIAC you had to rearrange a large number of patch cords and then locate three particular knobs on that vast 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 in 2.8 thousandths of a second; ENIAC's 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.; the program (sequence of computation steps) could be represented electronically just as the data was.

After the ENIAC• General protection fault/blue screen of death- modifications happen as fast as computers compute,

and could modify themselves as they ran; faulty logic in program could 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 Automatic Computer”;

first to employ magnetic tape• IBM became dominant company; “IBM and the seven dwarfs”; hired Microsoft to provide software

for personal computer (PC); by 2000 their market capitalization was twice 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 user logged in, typing on a teletype, which is a motorized typewriter that could transmit keystrokes to mainframe and print response on paper (type single text line, hit carriage return, 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 key punch 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 and

have exclusive use of it in dorm room• Microprocessor (uP) – A computer that is fabricated on an integrated circuit

(IC); first developed at Intel in 1971; put an entire computer on a chip; made a general purpose chip which could be reprogrammed for different tasks

• Program - A sequence of instructions stored in memory• Intel – Made the Intel 4004, the first uP, which had 2300 transistors and has

speed of 108 kHz; was on the Pioneer 10 spacecraft; then made 8008 and 8080 (the 8080 was employed in MITS Altair, the first PC); Pentium 4 has 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 IBM

standardized Intel uP for line of PCs in 1981; Pentium 4 is still compatible with 8088

Effects of computers on society, 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, do complicated 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 or laptop. The are used in all space missions now, and especially for things to dangerous for a human to do. Robots are possible because of computers.

Bibliography

• http://www.computersciencelab.com/ComputerHistory/History.htm