Introduction to the Science of Information Technology

In this course, you will look at the physical principles governing the operation of information systems. But first we should consider the definition of an information system. What distinguishes an information system from other electronic systems such as stereos and cash registers? If we removed certain components from a computer, would it still be an information system? This first reading will address these questions and establish an outline for the rest of the course.

Information Systems

Activity: If you haven't already done so in class, think about what functions are integral to an information system. What components are necessary? What components are common but not required? What operations should an information system be able to perform? Write down your thoughts. If you are working in a group, share your ideas and see if you can reach a consensus.

Components of Information Systems

As you thought about information systems, you probably considered different parts of a computer, such as the screen, the keyboard, and the mouse. You may have recognized the need for storage devices and a processor. You might also have thought about other peripheral devices such as speakers, a printer, and a modem. Methods of networking, such as modem lines, ethernet connections, and fiber optics could have been considered as well. Perhaps you came up with even more components. Certainly all of these devices can be found in many information systems, but they are not all necessary. Visually-impaired computer users have little use for a monitor. People with hearing loss would not benefit from speakers. Many "computer farms" used for research consist of little else than processors networked to each other and to tape drives. Considering these examples, we can see that many common features of information systems such as a mouse or a monitor are not essential to the definition of information systems.

Every information system must be able to do three things: process information, store information, and transfer information. Transferring information could be broken into two parts: input and output. Information storage can be temporary, such as RAM, or long-lasting, such as disks and tapes. But many items process, store and transfer information yet are not considered information systems. Consider a cash register, even a mechanical one that pre-dates computers. It can transfer information, receiving input from the clerk (or now the scanner) and outputting information to the receipt. It can store information temporarily in order to add prices. It can also process information by adding prices together, subtracting discounts, and adding tax. But is it an information system? Many other systems can be found which process store, and transfer information but would not really be considered information systems. Some examples are CallerID boxes, alarm clocks, and CD players.

What makes information systems distinct from the examples above is programmability and versatility. The cash register, CallerID box, clock, and CD player are all single-purpose machines. The CD player will not perform calculations, the cash register will not take exponents or logarithms, and the CallerID box won't print a phone list. Each of these devices has been designed for a particular purpose, and the user cannot program the device for any other purpose. An information system must be programmable, but programming by itself does not make an information system. A player piano is programmable, but one would hardly claim it qualifies as an information system.

As you can see from the above discussion, the distinction between an information system and other types of machines is not always easy to make. A mechanical cash register is not an information system, and primitive adding-machine-style calculators are probably not considered information systems. But some high-end calculators are hard to distinguish from laptop computers. Many calculators are programmable, and they execute programs faster than the early mainframe computers did. Surely the most sophisticated calculators could be considered information systems. Exactly where to draw the line between these two extremes is a matter of opinion.

An information system must be able to transfer information, both receiving input and sending output. It should be able to store information, both while performing operations and for longer periods of time. Finally, the information system must be able to process information in several different ways, according to a user-defined program.

Discussion Question: Should all calculators be considered information systems? If not, where do you draw the line? How would you determine whether a calculating machine is an information system?

Devices in Information Systems

Information systems store data in many different ways. Temporary storage that must be quickly accessed, such as RAM, generally uses electric storage devices such as capacitors and transistors. Magnetic disks are used in hard drives and floppy disks for frequent access, while magnetic tape often stores larger amounts of data that is accessed less often. Optical storage devices like CD-ROMs and DVDs were originally used to store information permanently, although erasable and writeable CD-ROMs have made optical storage more versatile.

Information transfer is accomplished through a variety of methods as well. In a typical computer farm, the input comes in the form of data from tapes, and the output is analyzed data on tape. It seems the user is unnecessary, except perhaps to replace tapes. But someone at some point had to tell the computer how to analyze the data. The program was originally input by a user. The user probably used a keyboard, but a mouse or a microphone could also be used. The output could take many forms as well, ranging from printed hard copies, to information on a monitor, to stored data. This information could be sent over coaxial cable ethernet wires, over a telephone wire, an ISDN wire, a cable, or over fiber optics.

Processing of information is done by transistors today, but transistors are not the only possibility. The first calculating machines were mechanical, using gears and switches to store and process numbers. Early computers used bulky vacuum tubes. The development of transistors, however, made personal computers affordable and small enough to sit on a desk. Many researchers are seeking the next form of processor that will replace transistors. Some of the possibilities are DNA, optical computers, and quantum computers.

Discussion Question: Do you think transistors will eventually be replaced? Why? What do you think will be the next breakthrough in computer technology?

Significant Events in Computer History (Optional)

Efforts at creating machines to assist in calculations date at least as far back as 3000 B.C., when the abacus was developed. Western efforts at calculating machines can be traced back to Leonardo da Vinci's sketches of about 1500 A.D. Today's laptops and the Internet bear little resemblance to the abacus or da Vinci's adding machine, yet they can trace their roots back to these early attempts. What follows is an outline of some of the significant advances in information technology through the centuries. Without each of these milestones in progress, we would not have the technology you are currently using to read this assignment!

c. 3000 B.C. Babylonia	The abacus, a mechanical calculating aid, developed Early civilizations calculated by arranging pebbles aruond lines in sand or dust. The modern form of the abacus, with beads on wires, apparently emerged in the 13th century A.D. The abacus remains in use today, although it requires an experienced user to effectively perform calculations with it.
c. 1500 A.D. Leonardo da Vinci	Thought of and sketched mechanical adding machine
1614 A.D. John Napier	Invented logarithms Logarithms may appear completely unrelated to the development of computing devices, but Napier's creations were very significant. Multiplication and division can be performed by adding and subtracting logarithms. This development meant that a machine capable of adding and subtracting could be used for multiplication and division as well. Napier is also remembered for his creation of Napier's bones, sticks with portions of multiplication tables on them that made multiplication of large numbers trivial to perform.
1623 A.D. Wilhelm Schickard	Built first mechanical adding machine (lost until 1900s) Schickard built a "Calculating Clock" that would perform addition and subtraction with gears. It also incorporated a set of Napier's bones for multiplication and subtraction. Sketches that Schickard sent to Kepler have survived, but the machine has not. Even the sketches disappeared for several centuries, so the Clock did not inspire future efforts. A reconstruction of the Clock was successfully built from the sketches in 1960.
1642 A.D. Blaise Pascal	Built and sold mechanical adding machine, the Pascaline Pascal's machine added using gears, but subtraction required the use of a mathematical trick. The Pascaline was delicate and could be fixed by no one but Pascal, so it did not achieve widespread usage. Pascal produced about 50 of them, and several of his machines did survive to influence other inventors.
1679 A.D. Gottfried Leibniz	Invented binary arithmetic One of the downfalls of early computing machines was their adherence to the decimal system. The Pascaline required ten distinguishable settings for each digit in a calculation. Machining gears to such precision was beyond the industrial standards of the times in which those gentlemen lived, and such mechanical difficulties were behind the failure of both the Pascaline and Babbages machines decribed below. Modern computers use Leibniz's binary arithmetic.
1700s	Special-purpose analog machines The 1700s saw the rise of many machines to aid navigation as well as a few more adding machines. While all are very interesting, none has any direct bearing on the evolution of the computer. See one of the histories listed in the Bibliography for more information on this time period.
1801 A.D. Joseph-Marie Jacquard	Developed automated loom using punched cards Jacquard revolutionized the weaving industry, and his innovation was recognized by Lovelace and Babbage as useful in calculating machines.
1822-1842 A.D. Charles Babbage	Developed and partially built mechanical Difference Engine Dreamed up mechanical Analytical Engine Babbage's Difference Engine was developed to produce mathematical tables using a technique called the method of constant differences. To eliminate typographical errors, the Engine would record results directly on metal plates - perhaps the first device with its own printer. The Analytical Engine would have been a much more versitile machine. Babbage's plans included the capacity to branch, or take alternate paths depending on a result. The Analytical Engine would have been able to loop, perform subroutines, and store up to 148 numbers. The program would be entered using punch cards. Babbage's creations were hampered by the lack of precision machining available at the time, as well as Babbage's reliance on the decimal system. Babbage's machines were large and ponderous - had the Analytical Engine been built, it would have filled a football field!
c. 1840 A.D. Lady Ada Augusta Lovelace	Suggested punch cards to Babbage Lovelace was a staunch supporter of Babbage, and much of what we know about Babbage's efforts is due to the writings of Lovelace. Lovelace drew Babbage's attention to Jacquard's looms, and she produced the programs for Babbage's Analytical Engine.
1847-1854 A.D. George Boole	Developed mathematical logic Boole was the first to apply mathematical concepts to logic. His Boolean algebra now composes the heart of all computing devices.
1890 A.D. Herman Hollerith	Built electromechanical Tabulating Machine to help with census Hollerith's machine counted rather than calculated, so it's design was much simpler than Babbage's ideas. Hollerith re-invented use of punch cards, and he used electricity to run the machine and send signals to the dials. Hollerith's Tabulating Machine Company, founded in 1896, later became IBM.
1930 A.D. Vannevar Bush	Built analog differential analyzer to solve differential euations Bush's machine was analog, not digital like the machines of Hollerith and Babbage. In an analog machine, numerical values vary continuously; in a digital machine only certain discrete numbers (like integers) are possible.
1932 A.D. C. E. Wynn-Williams	First large-scale application of digital electronics Wynn-Williams used digital electronics to build a binary counter for physics experiments in Cambridge. His idea caught on, and such usage was common by 1940.
1937 A.D. Alan Turing	Developed theory of computability - introduced the Turing machine Turing studied how people perform calculations and solve problems, then developed a simple model encompassing all possible logic actions. He had no intention of affecting computer science, but rather wanted to illustrate that logic could not provide proofs for every statement. Turing's machine, a purely theoretical creation, consists of an infinitely long tape with binary information on it, and a moving, programmable read/write head which can move along the tape. The head reads the symbol at its current location, then decides whether to change that symbol and what location to go to next based on its program. All three of the necessary components of an information system (processing, storage, transfer) are represented in the Turing machine, and the Turing machine can perform any procedure that modern processors can.
1938-1941 A.D. Conrad Zuse	Built electomechanical programmable computer Zuse did not know of the existing work on mechanical calculators, but started from scratch. He was the first to use a binary system in a calculating machine, and he recognized the need for a general-purpose programmable machine. Zuse also developed his own version of Boolean algebra for the logic portion of the computer. Zuse's first machine in 1938 was mechanical, but it was automatically controlled by a punch card reader. Later machines, such as the Z4, built in 1941, used electric relays. Zuse built memory and arithmetic units from electronic devices but never built an entirely electronic computer. Because of the isolation of Germany during World War II, Zuse's work went unnoticed by others in the field.
1939-1942 A.D. John Atanasoff and Clifford Berry	Built electronic digital computer - first to use vacuum tubes Atansoff and Berry's computer (ABC) was a special-purpose machine for solving systems of equations. The full machine was built in 1942. In addition to being the first machine to use vacuum tubes to calculate, the ABC incorporated binary arithmetic, regenerative electronic memory, and logic circuits. It was not, however, programmable. Antanasoff's machine was not patented, but he won a court battle in 1973 to be credited with the invention of the automatic electronic digital computer. This ruling was somewhat questionable, since the ABC was not automatic.
1940 A.D. George Stibitz and S. B. Williams	Built first multi-terminal remotely-accessible calculator Stibitz's ideas, combined with Williams' management, at Bell Labs produced this calculating device that could perform addition, subtraction, multiplication, and division on complex numbers. It used relays and binary mathematics, but it was not programmable. The Bell Complex Number Calculator was the first machine to serve more than one terminal (although it could serve only one at a time) and the first to be accessed from a remote location.
1942 A.D. John Mauchly	Wrote "The Use of High Speed Vacuum Tube Devices for Calculating" Mauchly believed electronic technologies were superior to mechanical technologies. His memo did not gain much attention at first, but it eventually led to the development of the ENIAC.
1943-1945 A.D. Ballistics Research Laboratory	Developed the Electronic Numerical Integrator and Computer Mauchly and a group at the Ballistics Research Laboratory built a calculating machine for trajectory calculations. ENIAC used 18000 vacuum tubes, 1500 relays, 70000 resistors, and 10000 capacitors. It weighed in at 30 tons and used between 140 and 174 kilowatts of power; the exact number is different in the different sources of the Bibliography. Some of ENIAC's complexity was due to Mauchly's decision to use decimal numbers, rather than binary. As the name suggests, ENIAC was developed to perform integration, but it was much more powerful than that. ENIAC had the capability of looping, performing subroutines, and following a program. Since ENIAC was primarily built for trajectory calculations, the machine had to be re-wired for other uses.
1947 A.D. Bardeen, Brattain, and Shockley	Invented transistor at Bell Telephone Laboratory Relays were slow, but vacuum tubes were expensive to run and prone to breakage. Transistors perform all of the electrical functions of vacuum tubes, but use little energy, generate little heat, turn on instantly, are sturdy and stable, and are cheap. Transistors have made possible the wide availability of computers outside of reasearch institutions and large corporations.
1948 A.D. Manchester Group	First electronic machine to perform stored program The Manchester machine demonstrated the ability to perform stored programs, but the memory was so limited (32 words of 32 bits each) in this prototype, it was not capable of performing complicated calculations. A larger, more useful version was produced by Ferranti Limited in 1951.
1948 A.D. Claude Shannon	Published theory of information science
1949 A.D. Maurice Wilkes	First machine capable of performing useful stored programs Wilkes and his colleagues at Cambridge built the Electronic Delay Storage Automatic Calculator. EDSAC could store 16 sets of 32 words of 17 bits each. This memory seems paltry by modern standards, but it was enough to make EDSAC versitile and useful.
1949 A.D. Prespert Eckert and John Mauchly	First computer system Eckert and Mauchly created the Universal Automatic Computer, a versitile data-processing system. UNIVAC had many possible components: printers, external long-term magnetic tape storage, converters between cards and tapes, tape copiers, and a processer to boot. Mauchly and Eckert continued to stick with decimal math, but UNIVAC's capabilities were revolotuionary. The RAM could hold 12000 digits or letters. UNIVAC could also process ten tapes at a time, and it could add numbers in 3/5 the time ENIAC needed.
1951 A.D. Jay Forrester and Bob Everett	First real-time computer, the Whirlwind. The idea for the Whirlwind grew out of an effort to create a real-time trainer-analyzer for Navy pilots' flight simulation. In order to speed calculations, words were limited for the first time to16 bits as opposed to the 40+ bits common in scientific computing. Some of the other innovations were the use of interactive monitors to facilitate its operation, multitasking, and the networking of multiple computers and other devices into one sytem. The Whirlwind demonstrated the potential of high-speed real-time general-purpose computers. It became the prototype for air traffic control and monitoring air space.
1951 A.D. Grace Hopper	Invented compiler Before the advent of compilers, even operators of programmable computers (as opposed to hard-wired machines) had to enter instructions in binary or, at best, a symbolic assembly language. Assembly languages varied by machine, and they were nothing more than translations of the binary commands. Programmers still had to enter every single command such as how to index the memory addresses, and computers could work only with integers. A compiler would take a single command from the user and automatically compile a list of binary operations to carry out that command. Hopper's initial compiler for the UNIVAC was only somewhat successful, but her idea caught on and led to the development of all modern computer languages.
1953 A.D. Jay Forrester	First use of magnetic core memory Computer memory was traditionally made of slow relays, slow magnetic drums, vacuum tubes prone to breakage, or cathode-ray tubes prone to breakage. Whirlwind's capability was limited by the performance of the thirty-two CRTs making up its 32768-bit internal memory. Once Forrester's idea of magnetic core memory was implemented, Whilrwind's operating speed doubled, and the amount of time needed for maintenence dropped by more than a factor of 10.
1957 A.D. John Backus	Developed compiler for first modern computer language - FORTRAN Backus' compiler initially had many bugs to work out, but it steadily improved and eventually led to the development of many other languages, such as COBOL and BASIC.
1958 A.D. Philco Corporation	First use of high-speed transistors in computers Transistors made their commercial debut in the Transac S-2000, produced by Philco Corporation.
1958 A.D. Jack Kilby	Produced first integrated circuit at Texas Instruments The idea of an integrated circuit IC) can be traced to a paper presented by G. W. A. Drummer in 1952. Kirby's IC was not elegant or extremely durable, but it proved that entire circuits could be produced on a single piece of semiconductor. A demonstration computer contained 587 of Kirby's ICs and weighed 10 ounces. It was comparable in computing power to a transistor computer with 8500 components and weighing 480 ounces. IC technology continued to develop, and a significant breakthrough was made in 1959 by Robert Noyce of Fairchild Semiconductor. Noyce developed a method that kept the circuit flat (planar), and this development led to the durability and commercial viability of today's integrated circuits. ICs were used fairly quickly in memory, but their encorporation in logic circuits took many years since they were incompatable with existing systems. Kilby shared the 2000 Nobel Prize in Physics for his invention.
1961 A.D. Steven Hofstein	Developed MOSFET The MOSFET is a type of transistor used in logic devices.
1963 A.D. Digital Equipment Corporation	First minicomputer, the PDP-8 Ken Olsen founded the Digital Equipment Corporation to produce smaller, less-powerful computers for businesses. The PDP-8 used transistors and magnetic core memory. It was limited, the memory having room for only 4K words of 12 bits each, but it was affordable to many, and its price fell as its popularity grew.
1969 A.D. Ted Hoff	Placed all circuits on one chip Ted Hoff, working for Intel, came up with the idea of making a general-purpose logic chip that could be used in any machine to perform any task. Up until this point, every application needed a different integrated circuit, and production of those circuits was falling well behind the demand. Hoff's microprocessor would be controlled by the ROM, which was programmed for the particular application. The first microprocessor was produced in 1970, and it could only process 4 bits of data at a time. An 8-bit processor capable of running a minicomputer was produced in 1972.
1971 A.D.	First fiber optic cable Fiber optic cables are noteworthy for the speed of information transfer as well as their low losses.
1974 A.D. Edward Roberts and MITS	Introduction of the personal computer Using one of Intel's chips, Edward Roberts and his company produced a kit for building a home computer. The Altair 8800 wasn't high-powered, it was affordable to the average person, and computer enthusiasts bought them in droves. Paul Allen and Bill Gates wrote the first BASIC compiler for the Altair soon after it was introduced. The company MITS did not survive, but it's legacy is the personal computer industry.

Disclaimer: The information in the above table has been compiled from several of the sources listed in the Bibliography below. Determining who did what first is often difficult, especially in periods of time when many advances were made simultaneously from several different groups of researchers. Many debates still rage about who deserves credit for what, and the sources used for the table do not always overlap or even agree. The table here is intended to give the reader an overview of several significant milestones in computer history. It is not intended to be a complete history of all developments in the field, and many significant people and machines are not included. Readers wanting more information or to learn about milestones not included in the table are encouraged to read the histories listed in the Bibliography.

Discussion Question: Which of the machines discussed above do you think represents the first information system? Why do you draw the line at that point? Discuss how earlier machines fall short of your criteria and how the machine you picked meets the criteria.

Science and Technology

Activity: If you haven't already done so in class, consider the distinction between Science and Technology. Both are used in the title of this course. Is there a difference? What are some examples of Science? What are some examples of Technology? For one of your examples of Technology, think about the Science behind the Technology. What scientific principles might be involved? Write down your thoughts. If you are working in a group, share your ideas and see if you can reach a consensus.

The Difference between Science and Technology

If you look up "technology" in a dictionary, the definition might be "applied science", or "the application of knowledge for practical ends".¹ Common to both of these definitions is application. Science, on the other hand, is defined as "systematic knowledge of the physical or material world gained through observation and experimentation".¹ Science is the knowledge; technology is the practical application of that knowledge.

Technologies are created and invented by people. Their worth is very environment-dependent, and evaluating their worth is quite subjective. The digital watch was viewed as a helpful technology in industrial societies. But a culture which uses the position of the sun rather than hours or minutes would have little use for the digital watch. Most modern computer systems rely heavily on the mouse and graphical interfaces. This technological advancement has enhanced the computing experience of countless users. Those who cannot see, however, may prefer keyboards and text-based operating systems. Technologies can be "faster", "more efficient", "less expensive", even "more advanced," but they are not "correct" or "incorrect."

Looking at information systems, the physical components are technology. The processor, the keyboard, the storage device are all examples of what we can build using scientific principles.

The science behind these technologies includes electromagnetism, optics, atomic structure, and quantum mechanics, and we will discuss each of these topics as they relate to the technology of information systems.

¹Random House Webster's College Dictionary (Random House: New York), 1991.

The Implications of Science on Technology

Technology is based on current scientific knowledge. Lasers, for example, work because electrons in atoms can only have certain values of energy. Had Bohr's theory of atom energies not been discovered, lasers would not have been invented yet. Science provides the foundation for technology.

In addition to allowing technology, science limits it. Technology can improve the efficiency of lasers, but scientific laws mandate that the energy contained in the laser beam cannot exceed the energy input the laser. Technology can devise better methods for fitting transistors on a chip, but science restricts the time required to send signals over a given distance. Fiber optics provide the capacity to transmit enormous amounts of data, but Shannon's theory of information still applies. No matter how much technology improves, it will still be subject to the limits of science.

New science could be discovered at any time, leading to new possibilities for technology. One should always keep in mind, however, that science is based on observation. Any new science must be consistent with current scientific theories when applied to phenomena now observed. Einstein's theory of relativity has usurped Newton's theories as the best description of gravitational effects. For earth-bound observations, however, Newton still works; the differences between Einstein's and Newton's theories are negligible for most situations. Thus the absolute limits on technology imposed by science are unlikely to change even if our scientific laws are revised.

The Science of Information Technology

Having determined what the necessary functions of information systems are, and the distinction between science and technology, we can now develop the concepts to be covered in the rest of this course. The course is a science course, in particular a physics course, so it will focus on the fundamental laws of nature. Topic from other sciences, such as binary math, logic, information theory, chemistry, and biology, are included in the course, but the primary focus will be the physical laws of nature. Expressing laws of nature in words is often cumbersome and ambiguous. Mathematics provides a well-defined shorthand as well as an effective vehicle for deduction. For this reason, mathematics is often called the language of physics. The materials for this course include a fair amount of algebra and trigonometry, along with occasional lapses into calculus. The calculus is included solely to present relationships in their most general and correct form. All expressions involving calculus will subsequently be applied to particular situations that do not need calculus. The student will need only the non-calculus expressions to complete the assignments. Assignments may, however, require the student to perform algebra and some trigonometry.

Information technology is the topic about which the course is organized. The subjects covered in the course have been selected for their relevance to information systems. Discussion of physical laws will be interspersed with applications of those laws to the processing, storage, and transfer of information. In particular, the course will examine the limits placed by science on each technology. The level of the course is appropriate for someone with no more physics background than perhaps a high school course. The topical approach, however, is sufficiently unique that even those with extensive physics backgrounds can learn much and gain a new appreciation for the interplay of science and technology.

Bibliography

Computing: The Technology of Information, by Tony Dodd. (Oxford University Press: New York), 1995.
A History of Computing Technology, 2nd ed., by Michael R. Williams (IEEE Computer Society Press: Los Alamitos, CA), 1997.