# Computer Systems Applications

MATHEMATICS spawned the computer in the 1940s and gave it its name. Its first application was the computation of theoretical ballistic tables for traditional bombs, but calculations for the atomic bomb and then for guided missiles soon became the driving force for computer development.
MATHEMATICS spawned the computer in the 1940s and gave it its name. Its first application was the computation of theoretical ballistic tables for traditional bombs, but calculations for the atomic bomb and then for guided missiles soon became the driving force for computer development.

### Computer Systems Applications

MATHEMATICS spawned the computer in the 1940s and gave it its name. Its first application was the computation of theoretical ballistic tables for traditional bombs, but calculations for the atomic bomb and then for guided missiles soon became the driving force for computer development. Many early electronic computers resembled their mechanical predecessors in that they could multiply or divide only by repeated execution of addition or subtraction operations, but their revolutionary speed and precision thrust them quickly into fields involving heavy multiplication. Thus, although computers were later to be emphasized as information system devices and applied to logical and sorting problems that did not involve multiplication or even significant addition, literal computing dominated the first decade and more of their use.

Working to 10 or so decimal places, computers brought a precision far beyond that of trigonometric and similar tables used in mathematics. They could readily construct improved tables, but instead, they were programmed to calculate from fundamentals, any needed value being ascertained from algebraic formulas or by iterative approximation (ie, repeating to produce a more and more nearly accurate solution). This concentration on basic values stimulated reconsideration and refinement of classical numerical methods (including their use of rounding off) to use the power and reduce the limitations of the new tool. The computer has been applied in turn to such esoteric mathematical questions as extending the number of decimal places for the known value of pi (which has an unlimited number of places) and ascertaining very large prime numbers (which are unlimited in number and size). For these and other ultra-precise calculations, complex software must be used to overcome the inherent limit to the number of significant digits for computer operations.

With the introduction late in the 1950s of solid-state components (the transistor for logic, the magnetic core for memory), the computer became much more widely available and its applications expanded rapidly outside of as well as within science. Census tabulation, a field with such heavy addition requirements that it had influenced developments in punched-card technology, lent itself to computerization, especially in North America, where computers were usually tied to card devices. The electronic computing of pay followed, particularly where hourly rates meant extensive multiplication. This step took the computer from the scientific world into that of commerce, and thus from the hands of the science graduate to those of the accountant and eventually the lay user. Computer functions soon moved from payroll into accounts receivable and other financial applications and into inventory control. Processing speed was the motivation, allowing the reduction of the size of inventory and of the delay in receiving payment, and hence decreasing tied-up funds. Energy utilities and insurance companies were among the pioneers in extending the use of computers beyond the payroll function. The addition of cathode-ray tubes for visual display of memory contents gave the user immediate access to data. Among the first to capitalize on this now widely used feature was AIR CANADA (for reservations).

### Aerospace

Atomic PHYSICS and missiles continued as the principal stimuli to computer development. The former, with its massive mathematical calculations from small data beginnings, drove relentlessly the creation of more powerful computers, while the latter, emerging as the AEROSPACE INDUSTRY, drove their miniaturization. Though also involving much heavy mathematics, the needs of the space industry related more to data handling, as multitudinous observations had to be processed to derive actual trajectories, to monitor performance via telemetry, and to control the craft. Many observers believe that American space achievements were completely dependent on computers (though the comparable Soviet achievements were very much less so). By the 1970s an extensive array of logic circuits or of memory could be etched onto a small chip of silicon, opening the way for the enormous proliferation of computer equipment and applications.

The earliest telemetry transmitted a radio signal of fixed frequency that varied in amplitude according to the reading of the thermometer or other instrument through which it had been passed. By sampling the received signal at intervals (eg, every hundredth of a second) and measuring its amplitude, the computer on the ground could know the internal conditions of the missile, allowing monitoring of performance and, with accelerometers among the instruments, could compute incrementally the implied position (as it does on a direct basis for inertial navigation systems). The sampling converted the continuously varying analog signal to the digital form required by the computer. The reverse process, of varying amplitude according to a timed series of digital values, allowed the computer to control the missile remotely and, similarly, to control the feed to a television set to produce a display of computer-held data; ie, the precursor of today's computer monitor. Applied within the frequency confines of telephony this brought the now-familiar modem (modulator-demodulator). Miniaturization allowed both telemetry and modems to be computer applications in themselves; it also permitted computers to store data within missiles and space probes, to control those vehicles, and ultimately to be reprogrammable remotely via radio links (see also SPACE TECHNOLOGY).

### Modelling

Using its essential ability to branch (ie, to take alternative paths according to conditions) and appropriate formulas and data, the computer can simulate real circumstances deterministically or probabilistically to assess alternative possible actions in support of decision-making (see ARTIFICIAL INTELLIGENCE) and for modelling, teaching and examination. The computer makes choices by exploring alternatives: it plays several steps down each feasible path and assesses the consequent situations. Traffic flow, command/supply economics and patient care are significant examples. By being able to assess alternatives, the computer has become a major force in recreational and competitive CHESS.

### Monitoring and Control

Given appropriate sensors, the computer can use its speed and stamina to provide vigilant monitoring of people as well as physical plants and to interpret a wide range of events (eg, construction of 3-dimensional images from X-ray data for CAT scanning and magnetic resonance imaging). A computer can react and hence control events in ways specified by program and human input. From transcontinental PIPELINES, refineries and NUCLEAR POWER PLANTS to traffic signals, building heating and ventilation, machine tools, car engines and automatic braking systems, down to the microwave oven and washing machine, the computer is widely in control. Interprovincial Pipe Line Ltd of Edmonton, ATOMIC ENERGY OF CANADA LTD and the City of Toronto were notable pioneers in these fields. Using early and cumbersome computers, the Canadian navy, with its DATARS Project, pioneered Command/Control of warships. Small, inexpensive microprocessors today allow computer control to be so unobtrusive as to make the presence of a computer go unnoticed. Minuscule size and energy demands allow computers to be used in a wristwatch or implanted in the human body to control an aberrant heart.

### Text

Compared with numbers, textual data is expensive to enter and store (because of its great inherent redundancy), and it lacks the notable profitability of automatic multiplication. Although these relative disadvantages cannot be eliminated, vast improvements in hardware economics in the 1970s (particularly of disc technology) lessened them and, with improved algorithms (definitions of the means of solving a problem, expressed in a language that the device understands), allowed routine storage of textual information and exploitation of electronic sorting beyond the primitive textual indexes of scientific literature abstracts promoted in the 1960s. Various forms of text editors have accommodated the computer's own source program material, as well as an ever-growing array of documents. Word processors evolved for simple correspondence, whereas software for desk-top publishing serves in the preparation of catalogues and books, and, because of its need for speed, in the NEWSPAPER industry.

Tied to laser-beam xerographic printers (embedding their own powerful processors and memories), the computer has become an information machine, able to produce personalized copies (of form letters, advertising material, etc,) rather than blind facsimiles in bulk, thus displacing the lead-type that had ruled printing for centuries. The emergence of the PC (personal computer) in the 1980s and its rapid enhancement through the escalation of chip capacities were crucial to these developments - but can be seen equally as driven by them, since they allowed the computer to be a superior typewriter affordable for the home. The simple word processor, using none of the computer's innate computationability, became the biggest factor in the vast proliferation of the machine.

### Pictures

Pictures are yet more demanding, but the great improvement in electronic storage has accommodated applications with very sophisticated visual images, in colour, with the computer capacity to reshape and vary views. At the simple level, a picture is just an array of dots - black and white or a mixture of suitable colours; fax represents the former, for which the in-built computer not only controls scanning and reproduction but also compaction over blank areas. Alternatively, pictures can be formed from multiple discrete objects, each an independent element within the computer data. In architecture and engineering, function, style and efficiency can all be addressed by computer-aided design (CAD) and then followed into the factory with computer-aided manufacturing (CAM).

Animated films are related derivatives using the computer to create the needed succession of images that show steady transformation between 2 scenes; Alias Research of Toronto is among the world leaders with this technology, which has created some major films of recent times. The high-quality picture achievable by computer is now displacing traditional art methods and material for many illustrations and for printed and film media. Special forms of graphics include complex scripts and music; for the latter, the inclusion of sound synthesizers allows computer-assisted composition.

### Telecommunications

Telephone lines have become a vital component of computer applications for connecting terminals to distant databanks, for interchange of data between computers and for e-mail and other facilities of the vast emerging world of the INTERNET. But the computer has become a vital component of the telephone network itself. Firstly, it took the place of electromechanical equipment that switches dial-up calls within the central offices (telephone exchanges). With the digitization of speech and other signals, it has gone on to provide voice-mail and various other user facilities, plus revised the whole TELECOMMUNICATION infrastructure to use digital rather than the inherent and traditional analog mode of signal. Unlike analog signals, digital signals can be controlled for error during transmission (and storage), allowing both higher quality and much greater use of any communication channel. The computer, as switching exchange and as part of modems, is essential to this control and enhances use further by compacting blank or otherwise repetitive data for transmission. By switching calls seamlessly between separate radio channels on separate stations serving adjacent areas ("cells") for cellular telephones, the computer has revolutionized both the quality and the economy of mobile radio telephony. All telephony is still in analog mode at the user level, but digital transmission is emerging, initially for the computer-equipped cellular handset. Digitized TELEVISION is already being provided by some satellites; with a computer in the receiver able to control and correct transmission errors, it heralds a great step up in picture quality (see also COMPUTER COMMUNICATIONS).

### Satellites

Public broadcasting satellites are positioned very high above the equator to keep them effectively stationary; other satellites orbit the Earth in various other, closer, paths. Many of these monitor surface or atmospheric conditions by computer (see REMOTE SENSING), relaying their digitized pictures to the ground where they may, like picture data from space probes, be elaborately enhanced by computer before being released. Another set of multiple satellites, each transmitting a tightly controlled radio signal from its known orbit and with 3 or more simultaneously in view, allows a portable computerized receiver on the ground to derive its position within a few metres, giving us the Global Positioning System. Installed in ships or trucks along with radio data-transmitters GPS units allow owners to know the whereabouts and monitor the use of their entire fleet. Installed in aircraft, they will soon make feasible completely automatic landing, navigation and even AIR TRAFFIC CONTROL (the University of Calgary being a leader in this field of geomatics). Installed in farm equipment along with satellite and other detailed data on surface conditions, they can control seed and fertilizer application, to the benefit of both the economy and the environment (see SATELLITE COMMUNICATIONS; SATELLITES, ARTIFICIAL).

### Everyday Life

From its rough laboratory beginnings the computer has come to embrace a limitless variety of applications, now generally using standardized components mass-produced at a minor unit cost. Tightly connected, they can meet the need for great concentrated power; loosely connected over distances, they meet the needs of a multitude of independent users while allowing them to communicate and to share data. Within a company office, a single network encompasses commercial and scientific applications, secretarial work, message communications and even speech communications (see OFFICE AUTOMATION). Outside, refinement of the public telecommunications networks is allowing any computer to talk to any other, making the world one network - the Internet, with easy 2-way correspondence (e-mail) and access to enormous libraries of promotional and educational information, all worldwide and at trivial direct cost.

The concept of the INFORMATION HIGHWAY has become part of everyday culture. With video on discs and using only its digital monitor and speakers, the computer has become a multimedia station (of major significance to COMPUTER-ASSISTED LEARNING). With elaborate attachments producing smell and tactile sensations as well as enclosed pictures and sound, the computer gives us, by comprehensive simulation, the world of virtual reality. As a toy or a tool, the computer now plays a significant role in the daily life of most Canadians, usually without them being aware that computers are involved.