EDP REVIEWER (1ST EXAM) PDF

COM PROG REVIEWER Counting Tables - Picture of ancient counting tables HISTORY OF COMPUTERS 1. Early computer operation(people) What is computer?...

COM PROG REVIEWER Counting Tables - Picture of ancient counting tables HISTORY OF COMPUTERS 1. Early computer operation(people) What is computer? An electronic device that can receive a set of instructions, or program, and then carry out this program by performing calculations on numerical data or by compiling and correlating other forms of information. What are computers? The first computers were people! That is, electronic computers (and the 2. Abacus earlier mechanical computers) were given this name because they performed the work that had previously been assigned to people. "Computer" was originally a job title: it was used to describe those human beings (predominantly women) whose job it was to perform the repetitive calculations required to compute such things as navigational tables, tide The abacus was an early aid for charts, and planetary positions for mathematical computations. Its only astronomical almanacs. value is that it aids the memory of the human performing the calculation. A Imagine you had a job where skilled abacus operator can work on hour after hour, day after day, you were addition and subtraction problems at the to do nothing but compute speed of a person equipped with a hand multiplications. Boredom would quickly calculator (multiplication and division are set in, leading to carelessness, leading slower). to mistakes. And even on your best days you wouldn't be producing answers The abacus is often wrongly attributed very fast. Therefore, inventors have to China. In fact, the oldest surviving been searching for hundreds of years abacus was used in 300 B.C. by the for a way to mechanize (that is, find a Babylonians. The abacus is still in use mechanism that can perform) this task. today, principally in the far east. John Napier 5. Leonardo da Vinci In 1617 an eccentric (some say mad) Scotsman named John Napier invented logarithms, which are a technology that allows multiplication to be performed via addition. Ex: log2x = 5 Leonardo da Vinci (1452-1519) made 3. Napier’s Bones drawings of gear-driven calculating machines but apparently never built any. 6. Calculating Clock The magic ingredient is the logarithm of each operand, which was originally obtained from a printed table. But Napier also invented an alternative to tables, where the logarithm values were carved on ivory sticks which are now The first gear-driven calculating called Napier's Bones. machine to actually be built was probably the calculating clock, so 4. Slide Rule named by its inventor, the German professor Wilhelm Schickard in 1623. This device got little publicity because Schickard died soon afterward in the bubonic plague. 7. Blaise Pascal Napier's invention led directly to the In 1642 Blaise Pascal, at age 19, slide rule, first built in England in 1632 invented the Pascaline as an aid for his and still in use in the 1960's by the father who was a tax collector. Pascal NASA engineers of the Mercury, Gemini, built 50 of this gear-driven one-function and Apollo programs which landed men calculator (it could only add) but couldn't on the moon. sell many because of their exorbitant cost and because they really weren't that accurate (at that time it was not possible to fabricate gears with the required precision). 8. Leibniz Up until the present age when car Just a few years after Pascal, the dashboards went digital, the odometer German Gottfried Wilhelm Leibniz portion of a car's speedometer used the (co-inventor with Newton of calculus) very same mechanism as the Pascaline managed to build a four-function to increment the next wheel after each (addition, subtraction, multiplication, and full revolution of the prior wheel. division) calculator that he called the stepped reckoner because, instead of 8-digit Pascaline gears, it employed fluted drums having ten flutes arranged around their circumference in a stair-step fashion. Although the stepped reckoner employed the decimal number system (each drum had 10 flutes), Leibniz was the first to advocate use of the binary number system which is fundamental to the operation of modern computers. Leibniz is considered one of the greatest of the philosophers but he died poor and alone. 6-digit Pascaline ( Cheaper ) Pascaline Insides  9. Jacquard Close up of a card In 1801 the Frenchman Joseph Marie Jacquard invented a power loom that Jacquard’s Loom - Close up of a could base its weave (and hence the tapestry woven by the loom design on the fabric) upon a pattern automatically read from punched wooden cards, held together in a long Technology -vs- Jobs row by rope. Descendents of these Jacquard's technology was a real boon punched cards have been in use ever to mill owners, but put many loom since (remember the "hanging chad" operators out of work. Angry mobs from the Florida presidential ballots of smashed Jacquard looms and once the year 2000?). attacked Jacquard himself. History is full of examples of labor unrest following Jacquard’s Loom technological innovation yet most - By selecting particular cards for studies show that, overall, technology Jacquard's loom you defined the has actually increased the number of woven pattern jobs. - The first significant use of binary automation 10. 1793-1871: Charles Babbage - Envisioned a steam-powered difference engine and then an analytical engine Charle’s Babbage By 1822 the English mathematician Charles Babbage was proposing a steam driven calculating machine the size of a room, which he called the Difference Engine. Difference Engine storage mechanism, holding - This machine would be able to computed numbers for future compute tables of numbers, such reference. as logarithm tables. - Because of the connection to the - He obtained government funding Jacquard loom, Babbage called for this project due to the the two main parts of his Analytic importance of numeric tables in Engine the "Store" and the "Mill", ocean navigation. as both terms are used in the - Construction of Babbage's weaving industry. Difference Engine proved - The Store was where numbers exceedingly difficult and the were held and the Mill was where project soon became the most they were "woven" into new expensive government funded results. project up to that point in English - In a modern computer these history. same parts are called the - Ten years later the device was memory unit and the central still nowhere near complete, processing unit (CPU). acrimony abounded between all - The Analytic Engine also had a involved, and funding dried up. key function that distinguishes The device was never finished. computers from calculators: the conditional statement. Babbage-Analytic Engine - A conditional statement allows a - Babbage was not deterred, and program to achieve different by then was on to his next results each time it is run. brainstorm, which he called the - Based on the conditional Analytic Engine. statement, the path of the - This device, large as a house and program can be determined powered by 6 steam engines, based upon a situation that is - It was programmable, thanks to detected at the very moment the the punched card technology of program is running. Jacquard. - Babbage saw that the pattern of Ada Byron holes in a punch card could be - Babbage befriended Ada Byron, used to represent an abstract the daughter of the famous poet idea such as a problem Lord Byron statement or the raw data - Though she was only 19, she required for that problem's was fascinated by Babbage's solution. ideas - Babbage realized that punched paper could be employed as a  - She began fashioning programs the 1890 census and this prize for the Analytic Engine, although was won by Herman Hollerith, still unbuilt. - The Analytic Engine remained 12. 1860-1929: Herman Hollerith unbuilt (the British government refused to get involved with this one) but Ada earned her spot in history as the first computer programmer. - Ada invented the subroutine and was the first to recognize the importance of looping. Devised a punched-card tabulating 11. 1816-1852: Lady Ada Augusta machine to speed up the 1890 U.S. Lovelace census Hollerith desk - The Hollerith desk, consisted of: - a card reader which sensed the holes in the cards, - a gear driven mechanism which could count (similar to Pascal’s) - A large wall of dial indicators to US Census display the results of the count. - The next breakthrough occurred in America. The U.S. Constitution states that a census should be taken of all U.S. citizens every 10 years in order to determine the representation of the states in Congress. - While the very first census of 1790 had only required 9 months, - Hollerith's technique was by 1880 the U.S. population had successful and the 1890 census grown so much that the count for was completed in only 3 years at the 1880 census took 7.5 years. a savings of 5 million dollars. Automation was clearly needed for the next census. - The census bureau offered a prize for an inventor to help with  how atmospheric drag, wind, gravity, muzzle velocity, etc. would determine the trajectory of the shell, but solving such equations was extremely Hollerith built a company, the laborious. Tabulating Machine Company - Human computers would which, after a few buyouts, compute results of these eventually became International equations and publish Business Machines, known today them in ballistic "firing as IBM. tables" - During World War II the Hollerith’s Inovation U.S. military scoured the country looking for (generally female) math majors to hire for the job of computing these tables, but not enough humans could be found to keep up with the need for new tables. - By using punch cards, - Sometimes artillery pieces Hollerith created a way to had to be delivered to the store and retrieve battlefield without the information. necessary firing tables and - This was the first type of this meant they were close read and write technology to useless because they couldn't be aimed properly. 13. US Military - Faced with this situation, - The U.S. military desired a the U.S. military was mechanical calculator willing to invest in even more optimized for hair-brained schemes to scientific computation. automate this type of - By World War II the U.S. computation. had battleships that could lob shells weighing as much as a small car over distances up to 25 miles. - Physicists could write the equations that described 14. Mark I The word "bug" had been used to describe a defect since at least 1889 but Hopper is credited with coining the word "debugging" to describe the work to eliminate program faults. - One early success was the Harvard Mark I computer which was built as a partnership between Harvard and IBM in 1944. 16. Humor - This was the first programmable On a humorous note, the principal digital computer made in the U.S. designer of the Mark I, Howard Aiken of - But it was not a purely electronic Harvard, estimated in 1947 that six computer. Instead the Mark I was electronic digital computers would be constructed out of switches, sufficient to satisfy the computing needs relays, rotating shafts, and of the entire United States. clutches. - The machine weighed 5 tons, The Future of Computers? incorporated 500 miles of wire, - IBM had commissioned this study was 8 feet tall and 51 feet long, to determine whether it should and had a 50 ft rotating shaft bother developing this new running its length, turned by a 5 invention into one of its standard horsepower electric motor. products (up until then computers - The Mark I ran non-stop for 15 were one-of-a-kind items built by years, sounding like a roomful of special arrangement). ladies knitting. - Aiken's prediction wasn't actually so bad as there were very few 15. The First Bug institutions (principally, the - One of the primary programmers government and military) that for the Mark I was a woman, could afford the cost of what was Grace Hopper. Hopper found the called a computer in 1947. first computer "bug": a dead moth - He just didn't foresee the that had gotten into the Mark I micro-electronics revolution  which would allow something like gears, cams, belts, shafts, etc.) an IBM Stretch computer of digital computer occurred in 1937 1959: by J. V. Atanasoff, - This machine was the first to First Generation Computers store data as a charge on a - The first electronic computer was capacitor, which is how today's designed at Iowa State between computers store information in 1939-1942 their main memory (DRAM or - The Atanasoff-Berry Computer dynamic RAM). As far as its used the binary system(1’s and inventors were aware, it was also 0’s). the first to employ binary - Contained vacuum tubes and arithmetic. stored numbers for calculations by burning holes in paper 3. Colussus - The Colossus, built during World War II by Britain for the purpose of breaking the cryptographic codes used by Germany. - Britain led the world in designing and building electronic machines dedicated to code breaking, and was routinely able to read coded Germany radio transmissions. - Not a general purpose, reprogrammable machine. 4. Eniac - The title of forefather of today's 2. Atanasoff – Berry Computer all-electronic digital computers is - One of the earliest attempts to usually awarded to ENIAC, which build an all-electronic (that is, no  stood for Electronic Numerical - The ENIAC used 18,000 vacuum Integrator and Calculator. tubes to hold a charge - ENIAC was built at the University - Vacuum tubes were so of Pennsylvania between 1943 notoriously unreliable that even and 1945 by two professors, twenty years later many John Mauchly and the 24 year neighborhood drug stores old J. Presper Eckert, who got provided a "tube tester" funding from the war department after promising they could build a machine that would replace all the "computers” - ENIAC filled a 20 by 40 foot Problems with the ENIAC room, weighed 30 tons, and used - The ENIAC used 18,000 vacuum more than 18,000 vacuum tubes. tubes to hold a charge - Vacuum tubes were so notoriously unreliable that even twenty years later many neighborhood drug stores provided a "tube tester" Replacing a vacuum tube Programming the ENIAC - To reprogram the ENIAC you had to rearrange the patch cords that you can observe on the left in the prior photo, and the settings of 3000 switches that you can observe on the right. The Stored Program Computer - To program a modern computer, - In 1945 John von Neumann you type out a program with presented his idea of a computer statements like: that would store computer - Circumference = 3.14 * diameter instructions in a CPU - To perform this computation on - The CPU(Central Processing ENIAC you had to rearrange a Unit) consisted of elements that large number of patch cords and would control the computer then locate three particular knobs electronically on that vast wall of knobs and set - The EDVAC, EDSAC and them to 3, 1, and 4. UNIVAC were the first computers  to use the stored program - Second generation computers concept also saw a new way data was - They used vacuum tubes so they stored were too expensive and too large - Punch cards were replaced with for households to own and afford magnetic tapes and reel to reel machines 5. Edvac 1. Univac - The UNIVAC computer was the first commercial (mass produced) - It took days to change ENIAC's computer. program. - In the 50's, UNIVAC (a - Eckert and Mauchly's next contraction of "Universal teamed up with the Automatic Computer") was the mathematician John von household word for "computer" Neumann to design EDVAC, just as "Kleenex" is for "tissue". which pioneered the stored - UNIVAC was also the first program. computer to employ magnetic - After ENIAC and EDVAC came tape. other computers with humorous names such as ILLIAC, JOHNNIAC, and, of course, MANIAC Second Generation Computers - In 1947, the transistor was invented - The transistor made computers smaller, less expensive and increased calculating speeds. Third Generation Computers 2. Time-Sharing - Transistors were replaced by integrated circuits(IC) - There were 2 ways to interact - One IC could replace hundreds of with a mainframe. transistors - The first was called time sharing - This made computers even because the computer gave each smaller and faster. user a tiny sliver of time in a round-robin fashion. Fourth Generation Computers - Perhaps 100 users would be simultaneously logged on, each typing on a teletype such as the following: 2. Teletype - A teletype was a motorized 1. Mainframe computers typewriter that could transmit - If you learned computer your keystrokes to the mainframe programming in the 1970's, you and then print the computer's dealt with what today are called response on its roll of paper. mainframe computers, such as - You typed a single line of text, hit the IBM 7090 (shown below), the carriage return button, and IBM 360, or IBM 370. waited for the teletype to begin noisily printing the computer's response 3. Batch-Mode Processing see a successful printout showing your results Programming Today - The alternative to time sharing - But things changed fast. By the was batch mode processing, 1990's a university student would where the computer gives its full typically own his own computer attention to your program. and have exclusive use of it in his - In exchange for getting the dorm room. computer's full attention at run-time, you had to agree to 1. Microprocessor prepare your program off-line on a key punch machine which generated punch cards. 4. Punch Cards - University students in the 1970's bought blank cards a linear foot at a time from the university - This transformation was a result bookstore. of the invention of the - Each card could hold only 1 microprocessor. program statement. - A microprocessor (uP) is a - To submit your program to the computer that is fabricated on an mainframe, you placed your stack integrated circuit (IC). of cards in the hopper of a card - Computers had been around for reader. 20 years before the first - Your program would be run microprocessor was developed at whenever the computer made it Intel in 1971. that far. - You often submitted your deck and then went to dinner or to bed and came back later hoping to Microprocessor 1. Apple 1 Computer - 1976 - The micro in the name microprocessor refers to the physical size. - Intel didn't invent the electronic computer, but they were the first 2. The IBM PC to succeed in cramming an entire computer on a single chip (IC) 2. Integrated Circuits 3. Commodore 64 - The microelectronics revolution is what allowed the amount of hand-crafted wiring seen in the prior photo to be mass-produced as an integrated circuit which is a small sliver of silicon the size of your thumbnail - Integrated circuits and 4. Apple Macintosh microprocessors allowed computers to be faster - This led to a new age of computers - The first home-brew computers is called the ALTAIR 8800 5. The Amiga 10. PowerPC 6. Windows 3 11. IBM OS/2 7. Macintosh System 7 12. Windows 95 8. Apple Newton 9. Standard UNIX COMPUTER GENERATIONS The Fourth Generation (1975 to Today) Early Electronic Computers and The These computers use Computer Generations microprocessor chips. Object-Oriented Programming The First Generation (1951 to 1959) (OOP) Languages such as Visual 1. Grace Hopper Basic, and JAVA are 2. J. Presper Eckert characteristic of this computer 3. Clfford Berry generation. 4. John Atanasoff 5. John von Neumann Object Oriented Languages 6. John Mauchly The new languages are based on 7. Howard Aiken a concept called Object-Oriented Programming (OOP) which Characterized by vacuum tubes encourages programmers to which burned out very rapidly. reuse code by maintaining The first generation of computers libraries of code segments. used machine language or 0s These programs are designed to and 1s. solve specific problems and This generation also used require little special user training. magnetic tape. This includes Query Languages and application generators The Second Generation (1959 to 1963) A Fifth Generation? The second generation of AI and Natural Languages computers used transistors for 5th Generation Still Being Developed the internal operations. They used magnetic core for the Natural Language memory. This language is designed to give These machines used assembly people a more human connection language. with computers. Uses multi-media has also The Third Generation (1963 to 1975) defined this generation. These computers used integrated There is a great deal of “bundled circuits on silicon chips. software” with this generation. They were characterized with high-level programming languages which required logic such as BASIC, Pascal, C, COBOL, and Fortran CATEGORIES OF COMPUTER 7. Embedded Computers – is a special purpose computer that functions as a component in 1. Personal Computer – is a a larger product. computer that can perform all of its input, processing, output and 8. Samples of Computer Usage storage activities by itself. Home Users – each family member spends time on the 2. Mobile Computer and Mobile computer for different reasons. Devices – Mobile Computer is a personal computer you can carry 9. Small Office / Home Office from place to place. Mobile Users – computers assist small Devices is a computing device businesses and home office in small enough to hold in your managing their resources hand. effectively. 3. Game Consoles – is a mobile 10. Mobile Users – who work on computing device designed for mobile computers or device while single player or multiplayer video away from home and main games. office, home office, or school. 4. Servers – controls access to the 11. Power Users – requires the hardware, software and other capabilities of a powerful resources on a network and desktop computer called stations. provides a centralized storage area for program, data and 12. Enterprise User – Each information. employee or customer who uses a computer in the 5. Mainframes – is a large enterprise. expensive, powerful computer that can handle hundreds or Computer Application in Society thousands of connected users Education Publishing simultaneously. Finance Travel Government 6. Supercomputer – is the fastest Manufacturing and the most powerful computer Health Care and the most expensive. Science