Misplaced Pages

#611388

77-496: It achieved success in the United Kingdom, with reviewers noting the system's high resolution 800 × 400 display (for its time) and its trackball cable (later models used IR). It used an Intel 8086 processor running at 4.77 MHz . A 8087 math co-processor was optional. The amount of memory was 256 kB , expandable to 768 kB . It came with a CRT green-screen 9" with text mode 80 × 25 or graphics 800 × 400 pixels and

154-519: A List of trackball arcade games ). In March 1978, Sega released World Cup , an association football game with trackball controls. In October 1978, Atari released Atari Football , which popularized the use of a trackball, with the game's developers mentioning it was inspired by an earlier Japanese association football game. Other notable trackball games include Atari's Centipede and Missile Command – Atari trademarked it "TRAK-BALL". Console trackballs, now fairly rare, were common in

231-428: A mouse , simplifying use in confined or cluttered areas such as a small desk or a rack-mounted terminal. They are generally preferred in laboratory setting for the same reason. Trackballs were often included in laptop computers, but since the late 1990s these have been replaced by touchpads and pointing sticks . Trackballs are still used as separate input devices with standard desktop computers, but this application

308-440: A scroll wheel like most mice, but the most common type is a “scroll ring” which is spun around the ball. Kensington's SlimBlade Trackball similarly tracks the ball itself in three dimensions for scrolling. As of 1989 and into the 2020s, two major companies developed and produce consumer trackballs, Logitech and Kensington , although Logitech has narrowed its product line to two models. Other smaller companies occasionally offer

385-408: A Fourier synthesizer, a tide-predicting machine , which summed the individual harmonic components. Another category, not nearly as well known, used rotating shafts only for input and output, with precision racks and pinions. The racks were connected to linkages that performed the computation. At least one U.S. Naval sonar fire control computer of the later 1950s, made by Librascope, was of this type, as

462-428: A comparatively intimate control and understanding of the problem, relative to digital simulations. Electronic analog computers are especially well-suited to representing situations described by differential equations. Historically, they were often used when a system of differential equations proved very difficult to solve by traditional means. As a simple example, the dynamics of a spring-mass system can be described by

539-495: A dense material such as phenolic resin , so they can be spun to make them coast. The trackball's buttons may be in similar positions to those of a mouse, or configured to suit the user. Large trackballs are common on CAD workstations for easy precision. Before the advent of the touchpad , small trackballs were common on portable computers (such as the BlackBerry Tour ) where there may be no desk space on which to run

616-627: A fully electronic analog computer at Peenemünde Army Research Center as an embedded control system ( mixing device ) to calculate V-2 rocket trajectories from the accelerations and orientations (measured by gyroscopes ) and to stabilize and guide the missile. Mechanical analog computers were very important in gun fire control in World War II, the Korean War and well past the Vietnam War; they were made in significant numbers. In

693-521: A mouse. Some small "thumballs" are designed to clip onto the side of the keyboard and have integral buttons with the same function as mouse buttons. The trackball was invented as part of a post- World War II -era radar plotting system named Comprehensive Display System (CDS) by Ralph Benjamin when working for the British Royal Navy Scientific Service. Benjamin's project used analog computers to calculate

770-400: A physical panel with connectors or, in more modern systems, as a software interface that allows virtual management of signal connections and routes. Output devices in analog machines can vary depending on the specific goals of the system. For example, they could be graphical indicators, oscilloscopes , graphic recording devices, TV connection module , voltmeter , etc. These devices allow for

847-488: A rolling deck could produce undesirable input. Trackballs are generally either thumb-operated, with a ball about an inch in diameter or smaller moved by one digit (almost always the thumb) and the buttons clicked by others, or finger-operated, with a ball over two inches in diameter operated by the middle fingers and the buttons by the thumb and little finger. Users favor one format or another for reasons of comfort, mobility, precision, or because it reduces strain on one part of

SECTION 10

#1732773201612

924-473: A scrambled directory listing with some files missing. Apricot later offered the possibility of converting the computer into an IBM compatible PC by replacing the motherboard with one equipped with an Intel 80286 processor. Trackball A trackball is a pointing device consisting of a ball held by a socket containing sensors to detect a rotation of the ball about two axes—like an upside-down ball mouse with an exposed protruding ball. Users roll

1001-655: A ship or submarine. Modern installations of such equipment may use mice instead, since most people now already know how to use one. However, military mobile anti-aircraft radars, commercial airliners (such as Airbus A380 and Airbus A350 ) and submarine sonars tend to continue using trackballs, since they can be made more durable and more fit for fast emergency use. Large and well made ones allow easier high precision work, for which reason they may still be used in these applications (where they are often called "tracker balls") and in computer-aided design . Trackballs have appeared in video games , particularly early arcade games (see

1078-458: A trackball in their product line. Microsoft produced popular models including The Microsoft Trackball Explorer, but has since discontinued all of its products. In September 2017 Logitech announced release of MX-Ergo Mouse, which was released after 6 years of its last trackball mouse. Large trackballs are sometimes seen on computerized special-purpose workstations, such as the radar consoles in an air-traffic control room or sonar equipment on

1155-404: A trackball is easier to manipulate and the buttons can be activated without affecting the pointer position. Trackball users also often state that they are not limited to using the device on a flat desk surface. Trackballs can be used whilst browsing a laptop in bed, or wirelessly from an armchair to a PC playing a movie. They are also useful for computing on boats or other unstable platforms where

1232-417: A very wide range of complexity. Slide rules and nomograms are the simplest, while naval gunfire control computers and large hybrid digital/analog computers were among the most complicated. Complex mechanisms for process control and protective relays used analog computation to perform control and protective functions. Analog computers were widely used in scientific and industrial applications even after

1309-444: A voltage on a particular wire). Therefore, each problem must be scaled so its parameters and dimensions can be represented using voltages that the circuit can supply —e.g., the expected magnitudes of the velocity and the position of a spring pendulum . Improperly scaled variables can have their values "clamped" by the limits of the supply voltage. Or if scaled too small, they can suffer from higher noise levels . Either problem can cause

1386-430: Is also moving to touchpads due to the prevalence of multi touch gesture control in new desktop operating systems. People with a mobility impairment use trackballs as an assistive technology input device. Access to an alternative pointing device has become even more important for them with the dominance of graphically-oriented operating systems. There are many alternative systems to be considered. The control surface of

1463-522: Is one of the few fields where slide rules are still in widespread use, particularly for solving time–distance problems in light aircraft. In 1831–1835, mathematician and engineer Giovanni Plana devised a perpetual-calendar machine , which, through a system of pulleys and cylinders, could predict the perpetual calendar for every year from AD 0 (that is, 1 BC) to AD 4000, keeping track of leap years and varying day length. The tide-predicting machine invented by Sir William Thomson in 1872

1540-513: Is striking in terms of mathematics. They can be modeled using equations of the same form. However, the difference between these systems is what makes analog computing useful. Complex systems often are not amenable to pen-and-paper analysis, and require some form of testing or simulation. Complex mechanical systems, such as suspensions for racing cars, are expensive to fabricate and hard to modify. And taking precise mechanical measurements during high-speed tests adds further difficulty. By contrast, it

1617-764: Is the PEAC (Practical Electronics analogue computer), published in Practical Electronics in the January 1968 edition. Another more modern hybrid computer design was published in Everyday Practical Electronics in 2002. An example described in the EPE hybrid computer was the flight of a VTOL aircraft such as the Harrier jump jet . The altitude and speed of the aircraft were calculated by

SECTION 20

#1732773201612

1694-497: Is to combine the two processes for the best efficiency. An example of such hybrid elementary device is the hybrid multiplier, where one input is an analog signal, the other input is a digital signal and the output is analog. It acts as an analog potentiometer, upgradable digitally. This kind of hybrid technique is mainly used for fast dedicated real time computation when computing time is very critical, as signal processing for radars and generally for controllers in embedded systems . In

1771-405: Is very inexpensive to build an electrical equivalent of a complex mechanical system, to simulate its behavior. Engineers arrange a few operational amplifiers (op amps) and some passive linear components to form a circuit that follows the same equations as the mechanical system being simulated. All measurements can be taken directly with an oscilloscope . In the circuit, the (simulated) stiffness of

1848-698: The IBM BIOS , so although it ran MS-DOS and CP/M-86 , it was not IBM PC compatible as the underlying system BIOS and hardware was very different. An Intel 8089 I/O controller was used, instead of the Intel 8237 DMA chip used in IBM computers; the ROM was only a simple boot loader rather than a full BIOS ; and there was no 640k barrier . The floppy disk format was "not quite compatible"; attempting to read an ordinary PC FAT floppy in an Apricot, or vice versa, would result in

1925-534: The Panther XL , which was based on the Assassin 3D. This combination provides for two-hand aiming and a high accuracy and consistency replacement for the traditional mouse and keyboard combo generally used on first-person shooter games. Many such games natively support joysticks and analog player movement, like Valve's Half-Life and id Software's Quake series . As of 2020 , one professional eSport player

2002-465: The spring constant and g {\displaystyle g} the gravity of Earth . For analog computing, the equation is programmed as y ¨ = − d m y ˙ − c m y − g {\displaystyle {\ddot {y}}=-{\tfrac {d}{m}}{\dot {y}}-{\tfrac {c}{m}}y-g} . The equivalent analog circuit consists of two integrators for

2079-489: The "Direct Analogy Electric Analog Computer" ("the largest and most impressive general-purpose analyzer facility for the solution of field problems") developed there by Gilbert D. McCann, Charles H. Wilts, and Bart Locanthi . Educational analog computers illustrated the principles of analog calculation. The Heathkit EC-1, a $ 199 educational analog computer, was made by the Heath Company, US c.  1960 . It

2156-465: The 1950s to the 1970s, general-purpose analog computers were the only systems fast enough for real time simulation of dynamic systems, especially in the aircraft, military and aerospace field. In the 1960s, the major manufacturer was Electronic Associates of Princeton, New Jersey , with its 231R Analog Computer (vacuum tubes, 20 integrators) and subsequently its EAI 8800 Analog Computer (solid state operational amplifiers, 64 integrators). Its challenger

2233-480: The BlackBerry range they were replaced by an "optical trackball" or " optical trackpad " before later being replaced with touch screens. In lieu of a scroll wheel , some mice include a tiny trackball sometimes called a scroll ball . A popular example is Apple's Mighty Mouse . Mice with a larger trackball on a side may be designed to stay stationary, using the trackball to move the mouse cursor instead of moving

2310-661: The Dumaresq were produced of increasing complexity as development proceeded. By 1912, Arthur Pollen had developed an electrically driven mechanical analog computer for fire-control systems , based on the differential analyser. It was used by the Imperial Russian Navy in World War I . Starting in 1929, AC network analyzers were constructed to solve calculation problems related to electrical power systems that were too large to solve with numerical methods at

2387-428: The advent of digital computers, because at the time they were typically much faster, but they started to become obsolete as early as the 1950s and 1960s, although they remained in use in some specific applications, such as aircraft flight simulators , the flight computer in aircraft , and for teaching control systems in universities. Perhaps the most relatable example of analog computers are mechanical watches where

Apricot PC - Misplaced Pages Continue

2464-568: The analog computer readout was limited chiefly by the precision of the readout equipment used, generally three or four significant figures. (Modern digital simulations are much better in this area. Digital arbitrary-precision arithmetic can provide any desired degree of precision.) However, in most cases the precision of an analog computer is absolutely sufficient given the uncertainty of the model characteristics and its technical parameters. Many small computers dedicated to specific computations are still part of industrial regulation equipment, but from

2541-679: The analog part of the computer and sent to a PC via a digital microprocessor and displayed on the PC screen. In industrial process control , analog loop controllers were used to automatically regulate temperature, flow, pressure, or other process conditions. The technology of these controllers ranged from purely mechanical integrators, through vacuum-tube and solid-state devices, to emulation of analog controllers by microprocessors. The similarity between linear mechanical components, such as springs and dashpots (viscous-fluid dampers), and electrical components, such as capacitors , inductors , and resistors

2618-414: The ball to position the on-screen pointer , using their thumb , fingers , or the palm of the hand , while using the fingertips to press the buttons. With most trackballs, operators have to lift their finger, thumb or hand and reposition in on the ball to continue rolling, whereas a mouse would have to be lifted itself and re-positioned. Some trackballs have notably low friction, as well as being made of

2695-592: The ball with the right thumb and pressing the buttons with the left thumb, thus giving the fingers a rest. Some mobile devices have trackballs, including those in the BlackBerry range, the T-Mobile Sidekick 3 , and many early HTC smartphones . These miniature trackballs are made to fit within the thickness of a mobile device, and are controlled by the tip of a finger or thumb. These have mostly been replaced on smartphones by touch screens, although on

2772-613: The ball. By counting the pulses, the physical movement of the ball could be determined. Since 1966, the American company Orbit Instrument Corporation produced a device named X-Y Ball Tracker , a trackball, which was embedded into radar flight control desks. A similar trackball device at the German Bundesanstalt für Flugsicherung  [ de ] was constructed by a team around Rainer Mallebrein  [ de ] of Telefunken Konstanz as part of

2849-407: The circuit to produce an incorrect simulation of the physical system. (Modern digital simulations are much more robust to widely varying values of their variables, but are still not entirely immune to these concerns: floating-point digital calculations support a huge dynamic range , but can suffer from imprecision if tiny differences of huge values lead to numerical instability .) The precision of

2926-434: The continuous and periodic rotation of interlinked gears drives the second, minute and hour needles in the clock. More complex applications, such as aircraft flight simulators and synthetic-aperture radar , remained the domain of analog computing (and hybrid computing ) well into the 1980s, since digital computers were insufficient for the task. This is a list of examples of early computation devices considered precursors of

3003-506: The development for the Telefunken computer infrastructure around the main frame TR 440  [ de ] , process computer TR 86 and video terminal SIG 100-86 , which began in 1965. This trackball was called Rollkugel (German for "rolling ball"). Somewhat later, the idea of "reversing" this device led to the introduction of the first computer ball mouse (still named Rollkugel , model RKS 100-86 ), which

3080-515: The early 1970s, analog computer manufacturers tried to tie together their analog computers with a digital computers to get the advantages of the two techniques. In such systems, the digital computer controlled the analog computer, providing initial set-up, initiating multiple analog runs, and automatically feeding and collecting data. The digital computer may also participate to the calculation itself using analog-to-digital and digital-to-analog converters . The largest manufacturer of hybrid computers

3157-452: The early 1980s: the Atari 2600 and 5200 consoles, as well as the competing ColecoVision console, though using a joystick as their standard controller, each had one as an optional peripheral . The Apple Pippin , a console introduced in 1996, had a trackball built into its gamepad as standard. Trackballs were occasionally used in e-sports prior to the mainstreaming of optical mice in

Apricot PC - Misplaced Pages Continue

3234-475: The early 2000s because they were more reliable than ball mice, but now they are extremely rare because optical mice offer superior speed and precision. Trackballs remain in use in pub golf machines (such as Golden Tee ) to simulate swinging the club. Trackballs have also been regarded as excellent complements to analog joysticks , as pioneered by the Assassin 3D, a trackball released in 1996 with joystick pass-through capability. Later in 1996, Mad Catz released

3311-432: The equation m y ¨ + d y ˙ + c y = m g {\displaystyle m{\ddot {y}}+d{\dot {y}}+cy=mg} , with y {\displaystyle y} as the vertical position of a mass m {\displaystyle m} , d {\displaystyle d} the damping coefficient , c {\displaystyle c}

3388-406: The future position of target aircraft based on several initial input points provided by a user with a joystick . Benjamin felt that a more elegant input device was needed and invented a ball tracker system called the roller ball for this purpose in 1946. The device was patented in 1947, but only a prototype using a metal ball rolling on two rubber-coated wheels was ever built and the device

3465-402: The hand/wrist. Most, but not all, finger-operated designs are symmetrical in design, making them usable by both hands , while thumb-operated designs are by their nature asymmetric or “handed,” allowing the smallest examples to be held in the air. Thumb-operated trackballs are not generally available in left-handed configurations, due to small demand. Some computer users prefer a trackball over

3542-419: The light, so the sensor produces electrical pulses to indicate that rotation is occurring. Mice used the same basic system for determining motion, but had the problem that the ball was in contact with the desk or mousepad . In order to provide smooth motion the balls were often covered with an anti-slip surface treatment, which was, by design, sticky. Rolling the mouse tended to pick up any dirt and drag it into

3619-530: The mathematical understanding of the Gibbs phenomenon of overshoot in Fourier representation near discontinuities. In a differential analyzer, the output of one integrator drove the input of the next integrator, or a graphing output. The torque amplifier was the advance that allowed these machines to work. Starting in the 1920s, Vannevar Bush and others developed mechanical differential analyzers. The Dumaresq

3696-414: The modern computers. Some of them may even have been dubbed 'computers' by the press, though they may fail to fit modern definitions. The Antikythera mechanism , a type of device used to determine the positions of heavenly bodies known as an orrery , was described as an early mechanical analog computer by British physicist, information scientist, and historian of science Derek J. de Solla Price . It

3773-439: The more common mouse for ergonomic reasons. There seems to be no conclusive evidence from studies performed to determine which type of pointing device works best for most applications. Application users are encouraged to test different devices, and to maintain proper posture and scheduled breaks for comfort. Some disabled users find trackballs easier since they only have to move their thumb relative to their hand, instead of moving

3850-516: The mouse. Analog computer An analog computer or analogue computer is a type of computation machine (computer) that uses physical phenomena such as electrical , mechanical , or hydraulic quantities behaving according to the mathematical principles in question ( analog signals ) to model the problem being solved. In contrast, digital computers represent varying quantities symbolically and by discrete values of both time and amplitude ( digital signals ). Analog computers can have

3927-561: The patch panel, various connections and routes can be set and switched to configure the machine and determine signal flows. This allows users to flexibly configure and reconfigure the analog computing system to perform specific tasks. Patch panels are used to control data flows , connect and disconnect connections between various blocks of the system, including signal sources, amplifiers, filters, and other components. They provide convenience and flexibility in configuring and experimenting with analog computations. Patch panels can be presented as

SECTION 50

#1732773201612

4004-670: The period 1930–1945 in the Netherlands, Johan van Veen developed an analogue computer to calculate and predict tidal currents when the geometry of the channels are changed. Around 1950, this idea was developed into the Deltar , a hydraulic analogy computer supporting the closure of estuaries in the southwest of the Netherlands (the Delta Works ). The FERMIAC was an analog computer invented by physicist Enrico Fermi in 1947 to aid in his studies of neutron transport. Project Cyclone

4081-478: The possible construction of such calculators, but he had been stymied by the limited output torque of the ball-and-disk integrators . Several systems followed, notably those of Spanish engineer Leonardo Torres Quevedo , who built various analog machines for solving real and complex roots of polynomials ; and Michelson and Stratton, whose Harmonic Analyser performed Fourier analysis, but using an array of 80 springs rather than Kelvin integrators. This work led to

4158-405: The potentiometer was then equivalent to the formula of the equation being solved. Multiplication or division could be performed, depending on which dials were inputs and which was the output. Accuracy and resolution was limited and a simple slide rule was more accurate. However, the unit did demonstrate the basic principle. Analog computer designs were published in electronics magazines. One example

4235-530: The roller. DATAR was similar in concept to Benjamin's display, but used a digital computer to calculate tracks, and sent the resulting data to other ships in a task force using pulse-code modulation radio signals. DATAR's trackball used four disks to pick up motion, two each for the X and Y directions. Several additional rollers provided mechanical support. When the ball was rolled, the pickup discs spun and contacts on their outer rim made periodic contact with wires, producing pulses of output with each movement of

4312-730: The speed of analog computers was their fully parallel computation, but this was also a limitation. The more equations required for a problem, the more analog components were needed, even when the problem wasn't time critical. "Programming" a problem meant interconnecting the analog operators; even with a removable wiring panel this was not very versatile. While a wide variety of mechanisms have been developed throughout history, some stand out because of their theoretical importance, or because they were manufactured in significant quantities. Most practical mechanical analog computers of any significant complexity used rotating shafts to carry variables from one mechanism to another. Cables and pulleys were used in

4389-445: The spring, for instance, can be changed by adjusting the parameters of an integrator. The electrical system is an analogy to the physical system, hence the name, but it is much less expensive than a mechanical prototype, much easier to modify, and generally safer. The electronic circuit can also be made to run faster or slower than the physical system being simulated. Experienced users of electronic analog computers said that they offered

4466-411: The state variables − y ˙ {\displaystyle -{\dot {y}}} (speed) and y {\displaystyle y} (position), one inverter, and three potentiometers. Electronic analog computers have drawbacks: the value of the circuit's supply voltage limits the range over which the variables may vary (since the value of a variable is represented by

4543-437: The system where it would clog the chopper wheels, demanding cleanup. In contrast the trackball is in contact only with the user's hand, which tends to be cleaner. In the late 1990s both mice and trackballs began using direct optical tracking which follows dots on the ball, avoiding the need for anti-slip surface treatment. As with modern mice, most trackballs now have an auxiliary device primarily intended for scrolling. Some have

4620-503: The time. These were essentially scale models of the electrical properties of the full-size system. Since network analyzers could handle problems too large for analytic methods or hand computation, they were also used to solve problems in nuclear physics and in the design of structures. More than 50 large network analyzers were built by the end of the 1950s. World War II era gun directors , gun data computers , and bomb sights used mechanical analog computers. In 1942 Helmut Hölzer built

4697-470: The visualization of analog signals and the representation of the results of measurements or mathematical operations. These are just general blocks that can be found in a typical analog computing machine. The actual configuration and components may vary depending on the specific implementation and the intended use of the machine. Analog computing devices are fast; digital computing devices are more versatile and accurate. The idea behind an analog-digital hybrid

SECTION 60

#1732773201612

4774-405: The whole hand, while others incur unacceptable fatigue of the thumb. Elderly people sometimes have difficulty holding a mouse still while double-clicking ; the trackball allows them to let go of the ball while using the button. At times when a user is browsing menus or websites rather than typing, it is also possible to hold a trackball in the right hand like a television remote control, operating

4851-537: Was Electronic Associates . Their hybrid computer model 8900 was made of a digital computer and one or more analog consoles. These systems were mainly dedicated to large projects such as the Apollo program and Space Shuttle at NASA , or Ariane in Europe, especially during the integration step where at the beginning everything is simulated, and progressively real components replace their simulated parts. Only one company

4928-660: Was Applied Dynamics of Ann Arbor, Michigan . Although the basic technology for analog computers is usually operational amplifiers (also called "continuous current amplifiers" because they have no low frequency limitation), in the 1960s an attempt was made in the French ANALAC computer to use an alternative technology: medium frequency carrier and non dissipative reversible circuits. In the 1970s, every large company and administration concerned with problems in dynamics had an analog computing center, such as: An analog computing machine consists of several main components: On

5005-498: Was a mechanical calculating device invented around 1902 by Lieutenant John Dumaresq of the Royal Navy . It was an analog computer that related vital variables of the fire control problem to the movement of one's own ship and that of a target ship. It was often used with other devices, such as a Vickers range clock to generate range and deflection data so the gun sights of the ship could be continuously set. A number of versions of

5082-465: Was an analog computer developed by Reeves in 1950 for the analysis and design of dynamic systems. Project Typhoon was an analog computer developed by RCA in 1952. It consisted of over 4,000 electron tubes and used 100 dials and 6,000 plug-in connectors to program. The MONIAC Computer was a hydraulic analogy of a national economy first unveiled in 1949. Computer Engineering Associates was spun out of Caltech in 1950 to provide commercial services using

5159-685: Was developed in the late 16th century and found application in gunnery, surveying and navigation. The planimeter was a manual instrument to calculate the area of a closed figure by tracing over it with a mechanical linkage. The slide rule was invented around 1620–1630, shortly after the publication of the concept of the logarithm . It is a hand-operated analog computer for doing multiplication and division. As slide rule development progressed, added scales provided reciprocals, squares and square roots, cubes and cube roots, as well as transcendental functions such as logarithms and exponentials, circular and hyperbolic trigonometry and other functions . Aviation

5236-687: Was discovered in 1901, in the Antikythera wreck off the Greek island of Antikythera , between Kythera and Crete , and has been dated to c.  150~100 BC , during the Hellenistic period . Devices of a level of complexity comparable to that of the Antikythera mechanism would not reappear until a thousand years later. Many mechanical aids to calculation and measurement were constructed for astronomical and navigation use. The planisphere

5313-722: Was equipped with two floppy discs and a keyboard with an integrated LCD display. The Apricot Xi was a similar computer released in 1984, with a hard drive instead of a second floppy-drive. Due to an IBM PC incompatible BIOS, trying to run a software package like dBase III would result in a system crash. The system was delivered with SuperCalc , and several system utilities, asynchronous communication, an emulator for IBM PC , Microsoft Basic-86 , Basic Personal and ACT Manager (a GUI for MS-DOS). Optionally available were Microsoft Word, Multiplan , WordStar , dBase II , C-Pascal, UCSD Pascal , C , Fortran , COBOL and Basic Compiler 5.35 . The manufacturer did not completely clone

5390-556: Was first described by Ptolemy in the 2nd century AD. The astrolabe was invented in the Hellenistic world in either the 1st or 2nd centuries BC and is often attributed to Hipparchus . A combination of the planisphere and dioptra , the astrolabe was effectively an analog computer capable of working out several different kinds of problems in spherical astronomy . The sector , a calculating instrument used for solving problems in proportion, trigonometry, multiplication and division, and for various functions, such as squares and cube roots,

5467-539: Was kept as a military secret. Production versions of the CDS used joysticks. The CDS system had also been viewed by a number of engineers from Ferranti Canada , who returned to Canada and began development of the Royal Canadian Navy's DATAR system in 1952. Principal designers Tom Cranston, Fred Longstaff and Kenyon Taylor chose the trackball as the primary input, using a standard five-pin bowling ball as

5544-414: Was known as offering general commercial computing services on its hybrid computers, CISI of France, in the 1970s. The best reference in this field is the 100,000 simulation runs for each certification of the automatic landing systems of Airbus and Concorde aircraft. After 1980, purely digital computers progressed more and more rapidly and were fast enough to compete with analog computers. One key to

5621-703: Was known for using a trackball. Trackballs are provided as the pointing device in some public internet access terminals . Unlike a mouse, a trackball can easily be built into a console, and cannot be ripped away or easily vandalized. Two examples are the Internet browsing consoles provided in some UK McDonald's outlets, and the BT Broadband Internet public phone boxes . This simplicity and ruggedness also makes them ideal for use in industrial computers. Because trackballs for personal computers are stationary, they may require less space for operation than

5698-409: Was of great utility to navigation in shallow waters. It used a system of pulleys and wires to automatically calculate predicted tide levels for a set period at a particular location. The differential analyser , a mechanical analog computer designed to solve differential equations by integration , used wheel-and-disc mechanisms to perform the integration. In 1876 James Thomson had already discussed

5775-421: Was offered as an alternative input device to light pens and trackballs for Telefunken's computer systems since 1968. In later trackball models the electrical contacts were replaced by an optical chopper wheel, which had small slots cut into it in rather than electrical contacts. With an LED for illumination from one side and an optical sensor on the other, rotation of the wheel periodically blocks and unblocks

5852-441: Was programmed using patch cords that connected nine operational amplifiers and other components. General Electric also marketed an "educational" analog computer kit of a simple design in the early 1960s consisting of two transistor tone generators and three potentiometers wired such that the frequency of the oscillator was nulled when the potentiometer dials were positioned by hand to satisfy an equation. The relative resistance of

5929-548: Was the principal computer in the Mk. 56 Gun Fire Control System. Online, there is a remarkably clear illustrated reference (OP 1140) that describes the fire control computer mechanisms. For adding and subtracting, precision miter-gear differentials were in common use in some computers; the Ford Instrument Mark I Fire Control Computer contained about 160 of them. Integration with respect to another variable

#611388