A.-
The origin of the computer
Digital Media, animation,simulation

DEVELOPMENT OF COMPUTER AND COMMUNICATIONS TECHNOLOGY
Historical development of computer interactivity historical context for the development and use of real time computing, timesharing, networking, software, and graphical user interfaces.

Computing Before Computers

While calculating technologies (numbering systems, counting stones, counting sticks, etc.) have existed since antiquity, machines for calculation date only from the seventeenth century. Until the late nineteenth century, these machines were curiosities found in gentlemen' s scientific cabinets.

In the late nineteenth century, however, big businesses emerged, management and ownership were separated, and tools were developed as control items for the professional managerial class. Mechanical desk calculators were one of these new office machines, together with the typewriter, cash register, duplicating equipment, and filing systems. In the half century from 1890 to 1940, the desk calculator was improved, with such new features as printing mechanisms and electromechanical power, and the technology was spread across a wide range of large and small businesses. In this same half century, three other calculating technologies emerged. A punched card tabulating system was developed for assembling and counting large amounts of data for the 1890 U.S. population census. This technology continued to be improved in this period and leased to government agencies and large companies, such as the railroads and insurance companies, to process their paperwork and keep track of inventories.

This was the origin of IBM. A completely independent tradition of analog computing developed in the engineering community, especially in the electric power industry, which became established in this same era.
Analog computing devices were useful for many physical problems involving continuous instead of discrete variable, but they tended to operate like laboratory equipment and be applicable to only one specific purpose. In the 1930s there were a few attempts to build automatic calculators that could conduct large numbers of calculations without human intervention, so as to meet the needs of scientists.

THE INVENTION OF THE COMPUTER

The Invention of the Computer All three of these calculating traditions influenced the electronic, stored program computer or "computer" for short. The computer emerged from the Allied effort in World War II to calculate ballistic tables for the many new guns and shells that were being introduced.

The story of the ENIAC calculator, developed at the University of Pennsylvania, and the follow-on stored-program computer EDVAC is well known and need not be repeated here. It is useful, however, to emphasize three features about the EDVAC: its electronic switching, which made it fast enough to carry out a wide variety of applications; its digital representation of numbers and method of calculation, which gave it enough precision and tractability to make it amenable to general- rather than special-purpose use; and its stored program capability, which allowed it to be programmed for different tasks and to carry them out automatically, without human intervention, once the instructions and data had been entered.

Its wide applicability is one main reason why the computer has been such an important and pervasive technology in the late twentieth century.

Many people use computers today to draw, or compose letters, or send electronic mail- none of which were anticipated applications in the early postwar years. Given the scientists, engineers, and military personnel who were involved in the design of the first computers, it is not surprising that there was only one kind of application in mind- a super calculator that could do the large numbers of calculations required for certain kinds of large military or scientific applications.

It is because of this conception that many people predicted that the United States would need no more than perhaps ten such machines to meet national demand. This is part of the same tradition as those people building automatic calculators in the 1930s. Although the computer eventually made obsolete all the older kinds of calculating technologies, except for inexpensive calculators and a few special-purpose calculating devices, these earlier types had a strong shaping force on the design, use, and understanding of computers.

Engineers from the burgeoning postwar aerospace industry built hybrid analog-digital computers to design aircraft wings. Computers were too expensive to be used in place of desktop calculators by most companies in the early postwar years, but this was to change in the 1970s when minicomputers and timesharing services became widely available.

Large businesses and government agencies that had been using punched card tabulating systems soon changed over to computers supplied by the computer manufacturing industry that grew up within a decade of the invention of the computer- an industry in which the most successful companies were the business machine manufacturers such as IBM, Burroughs, and NCR.

The design requirements for the data processing machine were different from those of the scientific calculator; the scientific calculator did many precise calculations with relatively little input and output of data, whereas the data processing machines did few, relatively imprecise calculations with large amounts of data input and output.

It was the market for data processing computers that allowed the computer industry to grow in the late 1950s and 1960s. There was one similarity between the scientific calculators and the data processing machines. Both operated in batch processing mode.

Large numbers of small problems were collected (placed together in a batch), generally on punched cards or punched paper tape, and run through the machine at one time.

There were two main reasons for this: it enabled the capital-intensive computers to be used efficiently, and it was somewhat easier to build machines that ran in this way. The efficiency of the operation of the machine came, however, at the expense of the efficiency of the user.

The user would submit his or her cards to the machine' s operator, and they would be stored until the machine was ready for the batch in which the program was included.

Usually a day went by before the user would get the results, and as often as not the computer would not have done any meaningful calculation because of the existence of a missing parenthesis in the instructions, or some other minor syntactical error in the machine- language that was the only language the machine would understand.

The batch mode was thus highly non-interactive: the time between human input and machine response was too great, the language of communication was too machine-like, and there existed an intermediary (the computer operator) between machine and user. Yet batch processing was entrenched as the mode of computing supplied by the computer industry.

REAL TIME!

Real-time Computing Perhaps the most important, but by no means the only, place in which the batch mode of operation was undermined and replaced by new modes of operating computers was MIT. MIT was at the cutting edge in computing. MIT had built its reputation as the leading engineering school in America on teaching and research that placed mathematical sciences at the core of engineering. Engineering problems became problems that were solved through calculation.

The electrical engineering department in the period between the two world wars was famous for its research on electrical power systems, its close connections with General Electric, and the multitude of analog and other computing devices it built and used. MIT resumed its work in computing after the war and continued to be one of the leading research and educational institutions in computing.

The first project at MIT that challenged the batch processing mode of operation had its origins in the war.
The MIT Servomechanisms Laboratory, which had been founded in 1941 to build computing and control devices used for such purposes as aiming guns and stabilizing aircraft, was asked by the U.S. Bureau of Aeronautics in 1943 to build a general purpose aircraft simulator, which could train pilots to fly any of the planes in the military' s arsenal.

A flight trainer was a mockup of a cockpit with instruments and controls attached to a control system. When a pilot "flew" the simulator, the control system sent appropriate data to the aircraft's instruments and mechanical arms would move the cockpit to simulate the pitch and yaw that would occur.Jay Forrester, the assistant director of the laboratory, began by designing a control system that was essentially an analog computer that could be programmed to simulate the particular plane that was being "flown". Forrester learned about digital computing at the end of the war and changed the control from an analog device to a digital computer.

Eventually the trainer became secondary and the goal was to build a digital computer that would serve this purpose. A batch processing computer was of no value for this application.

In order to provide a realistic simulation, as the pilot moved the throttle or the yoke stick the computer must be able immediately to process and communicate adjustments to the instrument panel and the arms that moved the cockpit.

Real time computing

This computation had to be done in so-called real time. Real time computing was much more difficult and expensive to implement. It took four times as long and forty times as much money as originally budgeted to complete this computer, known as Whirlwind. In the course of doing so, many innovations were introduced, such as magnetic core memory, light pens for entering data, and numerous new electronic circuits. Whirlwind served as the prototype for the control center computers in the SAGE air defense system.

The Russians had exploded their first nuclear bomb in 1949, and the Americans were worried that Russians could carry nuclear warheads in long-range bombers over the North Pole and into the United States.

It was decided therefore to establish a line of radar field stations that would communicate their raw data back to these control centers, where the computers would process the data from many field stations and display air traffic on an electronic screen.

This would be monitored to gain an early warning of an attack. The SAGE system was expensive, costing $8 billion by the time it was implemented- and immediately made obsolete by the introduction of Inter-Continental Ballistic Missiles. But the important point here is, it was critical that these computers operate in real time.

There was no value in using a batch processing computer to learn that a bomber had entered your air space the day before! IBM, which had built the SAGE computers, used the expertise to build an important civilian real-time system, the SABRE airline reservation system, which was fully operational in 1964, to track reservations as they were made by customers to airline representatives around the country and later the world. SABRE was interactive in some senses of the word.

The agent was able to communicate back and forth with the centralized reservation computer while the customer was there in person or on the telephone, and usually a booking could be made while the customer waited. From the company' s perspective, its booking department could interact with all of its field agents at one time, getting up to the minute information that would help it to maximize passenger loads and profits and limit irritations to customers by overbooking.

It was not interactive in the sense of allowing two human to interact. Thus, while communication was a critical part of the system, this was not a communication system for humans. .

TIMESHARING

Timesharing Another project at MIT at the same time as SAGE and SABRE were being developed, known as Project MAC, opened up another interactive alternative to batch processing. MIT was actively involved in using computers in graduate education and research in the 1950s.

Mixing charity with business purposes, IBM chairman Thomas Watson, Sr. had established a program to provide steep discounts- and occasionally free use- of IBM computers to universities. IBM had a long-term relationship with MIT and had supplied a computer to them that was used by both MIT and a New England regional consortium of colleges.

The MIT faculty had come to the conclusion that batch processing computers, as these IBM computers were, was not good for educational purposes. Programming lessons or research projects were most effective if students had many opportunities to run their programs, with short turnaround times.

Several members of the faculty began to develop plans for a computer that would serve this educational function well, with support from the National Science Foundation, which had begun to take over the role of support for university computing from the private sector as part of the overall national response to Sputnik.

The solution that MIT arrived at was timesharing. A number of different users, scattered around campus, could each sit at a terminal and type in his or her program.
The computer would move from one terminal to the next, devoting short bursts of attention to each terminal in term. If the number of users did not overload the system, the response time to each users was short- only a few seconds typically- so each user could feel as though they had the machine' s complete attention and that the programming and processing could go on in real time.

Timesharing was a very satisfactory technical solution to the educational application, but timesharing systems- especially ones with ample capacity for an educational institution- were very expensive.
The cost of developing a single timesharing system for MIT would have consumed most of the money NSF had allocated for providing computer facilities for the entire U.S. college and university system; so they reluctantly had to decline to fund the implementation of the research program they had initially supported.

At just this time in 1962, the Department of Defense Advanced Research Projects Agency (ARPA) had decided to open a computing office.

ARPA had been started by President Eisenhower in the late 1950s, partially in response to Sputnik, as a way to consolidate advanced technological research for the armed services in one place, so as to cut costs and avoid some of the intense interservice rivalries that had long existed. Within a year after starting the computing office, ARPA was spending more on computing research than the sum of all other government agencies combined.

MIT was one of the first recipients of ARPA computing support, receiving several million dollars for Project MAC to build the timesharing computer. The computer was a success, and it led the computer manufacturers- even a reluctant IBM- to begin building timesharing computers

COMPUTER UTILITY

The Computer Utility Some of the people associated with Project MAC began to speak of a computer utility. The choice of words was intentional, to associate with the water or electric utilities that people had in their homes. Computers were high capital items. Universities were unable to afford modest computers without government help.
Small businesses and individual homes could not possibly afford to buy their own computers. But terminals and dedicated telephone lines hooked up to a timesharing computer probably was something that colleges and even small businesses could afford, and some day the price might come down in price to a point where they could be installed in private homes.

A new computer service industry grew up in the late 1960s to provide timesharing services. IBM and General Electric, plus new companies such as Tymshare and University Computing Company, entered this business.
These companies were the darlings of the stock market for a few years, but in the early 1970s they experienced a quick and decisive market decline because they were all having trouble writing the software needed to operate their systems effectively.

The larger the number of users hooked to the system, the more difficult the software. Soon timesharing systems were being used only in special niche markets in science, engineering, and business, where there were no more than fifty users. Thus this mode of interactive computing was available then to a small community of users, but not to the wider community that the advocates of the computer utility had hoped for.

The prospect of having a computer utility in every home just like your electricity, natural gas, and water was not to happen at that time or through the technology of timesharing services. The next logical step after timesharing was networking.

Although the users of a particular timesharing system could be located anywhere (connected to the computer by a telephone line), in practice most of the users of a particular system were clustered in one small geographical region, such as on a university campus or on one campus of a industrial research laboratory. It was a centralized organizational structure, and the users could only interact with the one centralized computer.

However, if computers themselves could be networked together in some way, the users, from their terminals, could communicate through their computer to gain access to other computers at some distance- computers that had different data, different programs, or additional computing power or features. This was the basic idea of networking when it was first developed. Several groups independently came up with the idea of networking, but the organization that made it happen was ARPA.

ARPA was interested in enabling the different groups of researchers that it was supporting to make use of the software and hardware paid for by ARPA at other sites.

They also wanted to take advantage of the time zone differences across the country to get more use out of the facilities. East Coast researchers could make use of west coast computer facilities for several hours before west coast researchers would be getting up, and the reverse would be true at night.

The technology was developed with ARPA' s funding and strong encouragement, and the first system, hooking four computing centers, became fully operational in 1970. ARPANET proved to be extremely successful, and the number of nodes increased steadily throughout the 1970s. During the 1970s, ARPANET was restricted to use by certain military organizations and researchers at a handful of top research universities that had ARPA contracts. Other computer science researchers were clamoring to take advantage of the access to the net, as much for the email contact with the other senior members of the research community as for access to the facilities at other computer sites. Indeed, email had been a throw-in to the original design, almost an afterthought, but it proved to be perhaps the most popular aspect of networked computing in the 1970s and 1980s.

The National Science Foundation tried several times in the 1970s to build a network for the entire research community but were prevented from doing so for a long time by the Office of Management and Budget, which did not want NSF in the position of operating a service business, especially if it would be in competition with the private sector. Commercial network services first appeared in 1975, when Telcomp timesharing service was recast as Telnet networking service, under the chairmanship of Larry Roberts, one of the former program officers at ARPA.

By 1978 Telnet had nodes in 176 U.S. cities and 14 countries, as well as several competitors. NSF was able in 1978 to establish Theorynet to connect the researchers in theoretical computer science, and in the 1980s to build NSFNET, to connect all kinds of scientific researchers. Another important network was USENET, which was formed in 1978 for colleges that had been excluded from connection to ARPANET.

One important feature of USENET was its news system, which involved a kind of electronic bulletin board that enabled users to subscribe to news groups where like-minded people could exchange ideas.

By 1991 there were 35,000 nodes on the USENET and more than a million subscribers. Internet, Gopher, and World Wide Web One of the obstacles for the growth of networking was the military, which was concerned about the security of the information it sent over the ARPANET and hence was very cautious in accepting new users. This problem was resolved in 1982, when a special military network, MILNET, was established for secure military communications.

Another obstacle was that some organizations, notably including IBM and Digital Equipment Corporation, built proprietary networks built on technologies other than that used in ARPANET. People on DECNET, for example, were not able to communicate directly with those on ARPANET until internetworking was developed.

ARPA established protocols (i.e., ways of communicating) that enabled one network to talk with another, which resulted in the Internet. Although these protocols were developed in the early 1970s, they were not heavily used until the 1980s. In 1984 there were still only about a thousand host computers on the Internet (mainly for scientific and engineering researchers at universities), but by 1988 there were 50,000 hosts and by the following year there were 150,000.

The networked world had moved out of the military and the university and into the public domain. Today, users are familiar with using the Internet not only for email and news groups, but also for the ability to read and write electronic documents with multimedia enhancements. These are a recent development.

The World Wide Web, with its capability to incorporate multimedia into documents, was developed at the CERN High-Energy Physics Laboratory in Switzerland in 1989. And the first major search and retrieval tool was Gopher, developed at the University of Minnesota in 1991. Much more powerful search tools developed in the last few years have made Gopher obsolete.

Computer Access: Technological and Economic Issues One final issue that must be considered in any discussion of the history of computer interactivity is access. This has two dimensions, technological and economic. Unless computers were relatively easy to use, they would not be used by large numbers of people. Unless they were affordable, they also would not receive mass use.

There are many technological achievements that have gone into making computers more powerful, more easy to use, and more amenable to interactive use. These include the change from batch processing operating mode to real-time, networked mode. We will consider only two other innovations here. One is the development of software. One useful way of reading the history of software is as the story of the automation of computer programming and use.

The first computers were supplied by manufacturers with almost no software. This was in part because computers were regarded as fast calculators to be used by scientists, who were believed to have the capability of doing the programming themselves.

Even internal housekeeping chores, such as where inside the computer's memory to store a particular piece of data, had to be specified by the user. Software for these purposes and for debugging of programs began to appear in the early 1950s. In the late 1950s, the first programming languages, FORTRAN and COBOL, were developed, so that users could interact with the computer in languages that resembled scientific or business rather than machine language. In the 1960s an independent software industry grew up, which wrote programs for all sorts of applications. In the 1980s, with the advent of the personal computer, all kinds of software, such as word processing, became available off the shelf at reasonable prices.

Another advance was the graphical user interface that has been closely identified with the Apple Macintosh products- windows, icons, mouse, and pulldown menus- and is now available on all personal computers, which novice users find more intuitive and easier to use without training.
The original research in this area was conducted in the 1960s in two laboratories supported by ARPA. At the Human Factors Research Center at the Stanford Research Institute, Douglas Englbart and others built an Electronic Office, which would integrate text and pictures in an electronic format that was unprecedented then but commonplace today. One feature of the Electronic Office was the invention of the mouse.

The other group was located at the University of Utah, where ARPA supported a major group that was at the cutting-edge in research on computer graphics. In a doctoral dissertation completed in 1969, Alan Kay developed the idea of the Dynabook, which was a computer-driven, notebook sized device that could store vast amounts of data and incorporated sophisticated information-finding tools.

The problem was that the technology was not yet compact or inexpensive enough to devote such a machine to a single user, as Englbart and Kay had envisioned. With the invention of the microprocessor at Intel and the continuing drop in the price of semiconductor technology, it was finally possible to begin thinking in the early 1970s of building a small, personal computer.

The first group to do so was Xerox, in its research center in Palo Alto, California, where Robert Taylor (formerly of ARPA) led a group of computer scientists that included Alan Kay. They completed the Alto workstation in 1975, sold commercially in 1981 as a high-end personal computer known as the Xerox Star. It was a technical triumph, having all of the features we expect today, but it cost too much to succeed in the marketplace.

However, Steve Jobs of Apple toured the Xerox facilities and came away with the plans for the successful line of computers that Apple is now known for: the Macintosh computer, which was introduced in 1984 after making the same marketing mistake as Xerox with its too-expensive Lisa computer the previous year.

The other consideration about access is economic. Sitting at a terminal in a timesharing mode was better for interaction than working in the normal batch processing environment, but the best experience was to have your own computer.

In the 1950s, computers were affordable only to large organizations, and there the typical user did not have hands-on access to the computer, which was the only way to have an interactive experience in those days.

The only people who were able to gain hands-on experience were hackers at places such as MIT, where they could sign up for middle-of-the-night shifts during which they would have complete control of the machine.

In the late 1960s the first minicomputers were manufactured by companies such as Digital Equipment Corporation or Data General. These machines were affordable to research scientists for their individual laboratories or by small businesses.

A number of people became hooked on having their computer through their experience with minicomputers, and these people, such as Stephen Gray, who was the editor of Electronics magazine and founder of the Amateur Computer Society, were the ones who promoted the microcomputer industry.

what are computer graphics ?

The term 'computer graphics' as used in this context refers to a set of computer applications which can be used to produce images and animations which would have been impossible with the technology available only a few years ago.

what are computer graphics In the popular press, computer graphics sound wonderful. They mirror real life, if anything they are better. Computer users no longer have to struggle with arcane and cumbersome user interfaces.
Everything will be intuitive. Unfortunately it's not that simple. A recurring theme within discussion of this technology is that while there are some aspects of Computer Graphics and Virtual Reality which are easy there are some which present a host of new design problems (Wexelblat, 1993).

When we look at a TV screen or movie, it is much the same as looking through a window - except that the scenario and unfolding events are typically distant in place and time. When we look at a computer screen it is much the same, except that the scenario and events are now not 'real' but computer generated: the environment we are looking at is 'virtual', it is a representation of the real world (Slater and Wilbur, 1995).

To visualise is to bring something as a picture before the mind. This is exactly what the visualisation software and hardware systems are trying to achieve. For years, various visualisation tools have been developed to help scientists to have a better understanding of problems of their concern. These tools can be used to create something as simple as 2-D images such as graphs, or it can be used to generate complicated 3-D images (Jean et al, 1991). Advances in computer hardware technology have led to an increase in the power available to computer users. Major software houses have kept pace with these advances developing software which utilises the technology available. Many engineers are now familiar with three-dimensional CAD systems and use them routinely in their work place. Many specialised software/CAD packages have become available dealing with particular aspects of the minerals field, such as geology, mine design or land reclamation.

These packages also offer a range of features such as advanced graphical user interfaces, full three dimensional modelling and solid modelling options. These systems will continue to change as photo-realistic rendering and Virtual Reality options become more widespread. The term 'computer graphics' as used above refers to a set of computer applications which can be used to produce images and animations which would have been impossible with the technology available only a few years ago. To produce high resolution computer graphics a three dimensional geometry is defined using conventional CAD software.

A range of texture maps are then applied to create solid three dimensional objects (texture maps are the computer graphics equivalent of applying patterned wallpaper over an object). Lighting conditions are then defined and objects are viewed from a range of different camera positions. If enough time and effort is put into creating these worlds the images produced can be difficult to distinguish from photographic images. A more advanced feature available at the higher end of the graphics market is the ability to create sequences of rendered frames and thus display these as an animation, or film.