History of computing hardware

The history of computing hardware is the record of the ongoing effort to make computer hardware faster, cheaper, and capable of storing more data(SONY VGP-BPS8 battery).

Computing hardware evolved from machines that needed separate manual action to perform each arithmetic operation, to punched card machines, and then to stored-program computers(SONY VAIO VGN-FZ Battery). The history of stored-program computers relates first to computer architecture, that is, the organization of the units to perform input and output, to store data and to operate as an integrated mechanism (see block diagram to the right) (SONY VAIO VGN-FZ11S Battery). Secondly, this is a history of the electronic components and mechanical devices that comprise these units. Finally, we describe the continuing integration of 21st-century supercomputers, networks, personal devices(SONY vgp-bps9 battery), and integrated computers/communicators into many aspects of today's society. Increases in speed and memory capacity, and decreases in cost and size in relation to compute power, are major features of the history(sony vgp-bpl9 battery). As all computers rely on digital storage, and tend to be limited by the size and speed of memory, the history of computer data storage is tied to the development of computers(SONY VAIO VGN-FZ32 Battery).

Overview

Before the development of the general-purpose computer, most calculations were done by humans. Tools to help humans calculate were then called "calculating machines", by proprietary names(SONY VAIO VGN-FZ440N Battery), or even as they are now, calculators. It was those humans who used the machines who were then called computers(SONY VAIO VGN-FZ280E Battery); there are pictures of enormous rooms filled with desks at which computers (often young women) used their machines to jointly perform calculations, as for instance, aerodynamic ones required for in aircraft design. (SONY VAIO VGN-FZ460E Battery)

Calculators have continued to develop, but computers add the critical element of conditional response and larger memory, allowing automation of both numerical calculation and in general, automation of many symbol-manipulation tasks. Computer technology has undergone profound changes every decade since the 1940s(SONY VAIO VGN-FZ190 Battery).

Computing hardware has become a platform for uses other than mere computation, such as process automation, electronic communications, equipment control, entertainment, education, etc(SONY VAIO VGN-FZ150E Battery). Each field in turn has imposed its own requirements on the hardware, which has evolved in response to those requirements, such as the role of the touch screen to create a more intuitive and natural user interface(SONY VAIO VGN-FZ260E Battery).

Aside from written numerals, the first aids to computation were purely mechanical devices which required the operator to set up the initial values of an elementary arithmetic operation(SONY VAIO VGN-FZ140E Battery), then manipulate the device through manual manipulations to obtain the result. A sophisticated (and comparatively recent) example is the slide rule in which numbers are represented as lengths on a logarithmic scale and computation is performed by setting a cursor and aligning sliding scales(SONY VAIO VGN-FZ11l Battery), thus adding those lengths. Numbers could be represented in a continuous "analog" form, for instance a voltage or some other physical property was set to be proportional to the number. Analog computers, like those designed and built by Vannevar Bush before World War II were of this type(SONY VAIO VGN-FZ11z Battery). Or, numbers could be represented in the form of digits, automatically manipulated by a mechanical mechanism. Although this last approach required more complex mechanisms in many cases, it made for greater precision of results(SONY VAIO VGN-FZ11m Battery).

Both analog and digital mechanical techniques continued to be developed, producing many practical computing machines. Electrical methods rapidly improved the speed and precision of calculating machines(SONY VAIO VGN-FZ18m Battery), at first by providing motive power for mechanical calculating devices, and later directly as the medium for representation of numbers. Numbers could be represented by voltages or currents and manipulated by linear electronic amplifiers(SONY VAIO VGN-FZ21m Battery). Or, numbers could be represented as discrete binary or decimal digits, and electrically controlled switches and combinational circuits could perform mathematical operations(SONY VAIO VGN-FZ410 Battery).

The invention of electronic amplifiers made calculating machines much faster than their mechanical or electromechanical predecessors. Vacuum tube (thermionic valve) amplifiers gave way to solid state transistors(SONY VAIO VGN-FZ21 Battery), and then rapidly to integrated circuits which continue to improve, placing millions of electrical switches (typically transistors) on a single elaborately manufactured piece of semi-conductor the size of a fingernail(SONY VAIO VGN-FZ160 Battery). By defeating the tyranny of numbers, integrated circuits made high-speed and low-cost digital computers a widespread commodity.

Earliest true hardware

Devices have been used to aid computation for thousands of years, mostly using one-to-one correspondence with our fingers(SONY VAIO VGN-FZ210CE Battery). The earliest counting device was probably a form of tally stick. Later record keeping aids throughout the Fertile Crescent included calculi (clay spheres, cones, etc.) which represented counts of items, probably livestock or grains, sealed in containers. The use of counting rods is one example(SONY VAIO VGN-FZ38M Battery).

The abacus was early used for arithmetic tasks. What we now call the Roman abacus was used in Babylonia as early as 2400 BC. Since then, many other forms of reckoning boards or tables have been invented. In a medieval European counting house, a checkered cloth would be placed on a table, and markers moved around on it according to certain rules, as an aid to calculating sums of money(SONY VAIO VGN-FZ31z Battery).

Several analog computers were constructed in ancient and medieval times to perform astronomical calculations. These include the Antikythera mechanism and the astrolabe from ancient Greece (c. 150–100 BC) (Sony Vaio VGN-FZ31S battery), which are generally regarded as the earliest known mechanical analog computers. Other early versions of mechanical devices used to perform one or another type of calculations include the planisphere and other mechanical computing devices invented by Abū Rayhān al-Bīrūnī (c. AD 1000) (SONY VAIO VGN-FZ31E Battery); the equatorium and universal latitude-independent astrolabe by Abū Ishāq Ibrāhīm al-Zarqālī (c. AD 1015); the astronomical analog computers of other medieval Muslim astronomers and engineers; and the astronomical clock tower of Su Song (c. AD 1090) during the Song Dynast(SONY VAIO VGN-FZ31J Battery)y.

The "castle clock", an astronomical clock invented by Al-Jazari in 1206, is thought to be the earliest programmable analog computer. It displayed the zodiac, the solar and lunar orbits(SONY VAIO VGN-FZ31M Battery), a crescent moon-shapedpointer traveling across a gateway causing automatic doors to open every hour, and five robotic musicians who play music when struck by levers operated by a camshaft attached to a water wheel. The length ofday and night could be re-programmed every day in order to account for the changing lengths of day and night throughout the year(SONY VAIO VGN-FZ31B Battery).

Scottish mathematician and physicist John Napier noted multiplication and division of numbers could be performed by addition and subtraction, respectively, of logarithms of those numbers(HP PAVILION DV6000 battery). While producing the first logarithmic tables Napier needed to perform many multiplications, and it was at this point that he designed Napier's bones, an abacus-like device used for multiplication and division(SONY VGP-BPS13 Battery). Since real numbers can be represented as distances or intervals on a line, the slide rule was invented in the 1620s to allow multiplication and division operations to be carried out significantly faster than was previously possible(SONY VGP-BPS13B/B Battery). Slide rules were used by generations of engineers and other mathematically involved professional workers, until the invention of the pocket calculator.

Wilhelm Schickard, a German polymath, designed a calculating clock in 1623, unfortunately a fire destroyed it during its construction in 1624 and Schickard abandoned the project(Dell INSPIRON 1525 battery). Two sketches of it were discovered in 1957; too late to have any impact on the development of mechanical calculators.

In 1642, while still a teenager, Blaise Pascal started some pioneering work on calculating machines and after three years of effort and 50 prototypes he invented the mechanical calculator. He built twenty of these machines (called thePascaline) in the following ten years(Dell INSPIRON E1505 battery).

Gottfried Wilhelm von Leibniz invented the Stepped Reckoner and his famous cylinders around 1672 while adding direct multiplication and division to the Pascaline. Leibniz once said "It is unworthy of excellent men to lose hours like slaves in the labour of calculation which could safely be relegated to anyone else if machines were used(Dell INSPIRON 1420 battery)."

Around 1820, Charles Xavier Thomas created the first successful, mass-produced mechanical calculator, the Thomas Arithmometer, that could add, subtract, multiply, and divide. It was mainly based on Leibniz' work(Dell INSPIRON 1520 battery). Mechanical calculators, like the base-ten addiator, the comptometer, the Monroe, the Curta and the Addo-X remained in use until the 1970s. Leibniz also described the binary numeral system(Dell INSPIRON 1464 battery), a central ingredient of all modern computers. However, up to the 1940s, many subsequent designs (including Charles Babbage's machines of the 1822 and even ENIAC of 1945) were based on the decimal system; ENIAC's ring counters emulated the operation of the digit wheels of a mechanical adding machine(Dell INSPIRON 1564 battery).

In Japan, Ryōichi Yazu patented a mechanical calculator called the Yazu Arithmometer in 1903. It consisted of a single cylinder and 22 gears, and employed the mixed base-2 and base-5 number system familiar to users to the soroban (Japanese abacus) (Dell INSPIRON 1764 battery). Carry and end of calculation were determined automatically. More than 200 units were sold, mainly to government agencies such as the Ministry of War and agricultural experiment stations(Dell N3010 Battery).

1801: punched card technology

In 1801, Joseph-Marie Jacquard developed a loom in which the pattern being woven was controlled by punched cards. The series of cards could be changed without changing the mechanical design of the loom(SONY VGP-BPS13/B Battery). This was a landmark achievement in programmability. His machine was an improvement over similar weaving looms. Punch cards were preceded by punch bands, as in the machine proposed by Basile Bouchon. These bands would inspire information recording for automatic pianos and more recently NC machine-tools(Sony VAIO VGN-FZ15T Battery).

In 1833, Charles Babbage moved on from developing his difference engine (for navigational calculations) to a general purpose design, the Analytical Engine, which drew directly on Jacquard's punched cards for its program storage(Sony VAIO VGN-FZ15G Battery). In 1835, Babbage described his analytical engine. It was a general-purpose programmable computer, employing punch cards for input and a steam engine for power, using the positions of gears and shafts to represent numbers(SONY VGP-BPS13A/S Battery). His initial idea was to use punch-cards to control a machine that could calculate and print logarithmic tables with huge precision (a special purpose machine). Babbage's idea soon developed into a general-purpose programmable computer(SONY VGP-BPS13AS Battery). While his design was sound and the plans were probably correct, or at least debuggable, the project was slowed by various problems including disputes with the chief machinist building parts for it(SONY VGP-BPS13S Battery). Babbage was a difficult man to work with and argued with everyone. All the parts for his machine had to be made by hand. Small errors in each item might sometimes sum to cause large discrepancies(SONY VGP-BPS13B/S Battery). In a machine with thousands of parts, which required these parts to be much better than the usual tolerances needed at the time, this was a major problem. The project dissolved in disputes with the artisan who built parts and ended with the decision of the British Government to cease funding. Ada Lovelace, Lord Byron's daughter(SONY VAIO PCG-5G2L battery), translated and added notes to the "Sketch of the Analytical Engine" by Federico Luigi, Conte Menabrea. This appears to be the first published description of programming(SONY VAIO PCG-5G3L battery).

A reconstruction of the Difference Engine II, an earlier, more limited design, has been operational since 1991 at the London Science Museum. With a few trivial changes, it works exactly as Babbage designed it and shows that Babbage's design ideas were correct, merely too far ahead of his time(SONY VAIO PCG-5J1L battery). The museum used computer-controlled machine tools to construct the necessary parts, using tolerances a good machinist of the period would have been able to achieve(SONY VAIO PCG-5K2L battery). Babbage's failure to complete the analytical engine can be chiefly attributed to difficulties not only of politics and financing, but also to his desire to develop an increasingly sophisticated computer and to move ahead faster than anyone else could follow(SONY VAIO PCG-5L1L battery).

Following Babbage, although unaware of his earlier work, was Percy Ludgate, an accountant from Dublin, Ireland. He independently designed a programmable mechanical computer, which he described in a work that was published in 1909(SONY VAIO PCG-5J2L battery).

In the late 1880s, the American Herman Hollerith invented data storage on a medium that could then be read by a machine. Prior uses of machine readable media had been for control (automatons such as piano rolls or looms), not data(SONY VAIO PCG-6S2L battery). "After some initial trials with paper tape, he settled on punched cards..." Hollerith came to use punched cards after observing how railroad conductors encoded personal characteristics of each passenger with punches on their tickets(SONY VAIO PCG-6S3L battery). To process these punched cards he invented the tabulator, and the key punch machine. These three inventions were the foundation of the modern information processing industry. His machines used mechanical relays (and solenoids) to increment mechanical counters(SONY VAIO PCG-6V1L battery). Hollerith's method was used in the 1890 United States Census and the completed results were "... finished months ahead of schedule and far under budget". Indeed years faster than the prior census had required. Hollerith's company eventually became the core ofIBM(SONY VAIO PCG-6W1L battery). IBM developed punch card technology into a powerful tool for business data-processing and produced an extensive line of unit record equipment. By 1950, the IBM card had become ubiquitous in industry and government(SONY VAIO PCG-7111L battery). The warning printed on most cards intended for circulation as documents (checks, for example), "Do not fold,spindle or mutilate," became a catch phrase for the post-World War II era(SONY VAIO PCG-6W3L battery).

Leslie Comrie's articles on punched card methods and W.J. Eckert's publication of Punched Card Methods in Scientific Computation in 1940, described punch card techniques sufficiently advanced to solve some differential equations or perform multiplication and division using floating point representations(SONY VAIO PCG-7113L battery), all on punched cards andunit record machines. Those same machines had been used during World War II for cryptographic statistical processing. In the image of the tabulator (see left), note thepatch panel, which is visible on the right side of the tabulator. A row of toggle switches is above the patch pane(SONY VAIO PCG-7133L battery)l. The Thomas J. Watson Astronomical Computing Bureau, Columbia Universityperformed astronomical calculations representing the state of the art in computing(SONY VAIO PCG-7Z1L battery).

Computer programming in the punch card era was centered in the "computer center". Computer users, for example science and engineering students at universities, would submit their programming assignments to their local computer center in the form of a stack of punched cards(SONY VAIO PCG-7Z2L battery), one card per program line. They then had to wait for the program to be read in, queued for processing, compiled, and executed. In due course, a printout of any results, marked with the submitter's identification(SONY VAIO PCG-8Y1L battery), would be placed in an output tray, typically in the computer center lobby. In many cases these results would be only a series of error messages, requiring yet another edit-punch-compile-run cycle. Punched cards are still used and manufactured to this day(SONY VAIO PCG-8Y2L battery), and their distinctive dimensions (and 80-column capacity) can still be recognized in forms, records, and programs around the world. They are the size of American paper currency in Hollerith's time, a choice he made because there was already equipment available to handle bills(SONY VAIO PCG-8Z2L battery).

Desktop calculators

By the 20th century, earlier mechanical calculators, cash registers, accounting machines, and so on were redesigned to use electric motors, with gear position as the representation for the state of a variable(SONY VAIO PCG-8Z1L battery). The word "computer" was a job title assigned to people who used these calculators to perform mathematical calculations. By the 1920s Lewis Fry Richardson's interest in weather prediction led him to propose human computersand numerical analysis to model the weather(SONY VAIO PCG-7112L battery); to this day, the most powerful computers on Earth are needed to adequately model its weather using the Navier-Stokes equations.

Companies like Friden, Marchant Calculator and Monroe made desktop mechanical calculators from the 1930s that could add(SONY VAIO PCG-6W2L battery), subtract, multiply and divide. During theManhattan project, future Nobel laureate Richard Feynman was the supervisor of the roomful of human computers, many of them female mathematicians, who understood the use of differential equations which were being solved for the war effort(SONY VAIO PCG-5K1L battery).

In 1948, the Curta was introduced. This was a small, portable, mechanical calculator that was about the size of a pepper grinder. Over time, during the 1950s and 1960s a variety of different brands of mechanical calculators appeared on the market(SONY pcga-bp2ea battery). The first all-electronic desktop calculator was the British ANITA Mk.VII, which used a Nixie tube display and 177 subminiature thyratron tubes. In June 1963, Friden introduced the four-function EC-130(SONY VGP-BPS21A/B Battery). It had an all-transistor design, 13-digit capacity on a 5-inch (130 mm) CRT, and introduced Reverse Polish notation (RPN) to the calculator market at a price of $2200. The EC-132 model added square root and reciprocal functions(SONY VGP-BPS21B Battery). In 1965, Wang Laboratories produced the LOCI-2, a 10-digit transistorized desktop calculator that used a Nixie tube display and could compute logarithms.

In the early days of binary vacuum-tube computers, their reliability was poor enough to justify marketing a mechanical octal version ("Binary Octal") of the Marchant desktop calculator. It was intended to check and verify calculation results of such computers(SONY VGP-BPS21 Battery).

Advanced analog computers

Before World War II, mechanical and electrical analog computers were considered the "state of the art", and many thought they were the future of computing. Analog computers take advantage of the strong similarities(SONY VGP-BPS21/S Battery) between the mathematics of small-scale properties—the position and motion of wheels or the voltage and current of electronic components—and the mathematics of other physical phenomena, for example, ballistic trajectories(SONY Vaio PCG-F305 battery), inertia, resonance, energy transfer, momentum, and so forth. They model physical phenomena with electrical voltagesand currents as the analog quantities(SONY VGP-BPS13A/Q Battery).

Centrally, these analog systems work by creating electrical analogs of other systems, allowing users to predict behavior of the systems of interest by observing the electrical analogs(SONY VGN NR11Z/T battery). The most useful of the analogies was the way the small-scale behavior could be represented with integral and differential equations, and could be thus used to solve those equations. An ingenious example of such a machine, using water as the analog quantity, was the water integrator built in 1928; an electrical example is the Mallock machine built in 1941(SONY VGN NR11Z/S battery). A planimeter is a device which does integrals, using distance as the analog quantity. Unlike modern digital computers, analog computers are not very flexible, and need to be rewired manually to switch them from working on one problem to another(SONY VGN NR11M/S battery). Analog computers had an advantage over early digital computers in that they could be used to solve complex problems using behavioral analogues while the earliest attempts at digital computers were quite limited.

Some of the most widely deployed analog computers included devices for aiming weapons(SONY VGN NR11S/S battery), such as the Norden bombsight and the fire-control systems, such asArthur Pollen's Argo system for naval vessels. Some stayed in use for decades after World War II; the Mark I Fire Control Computer was deployed by the United States Navy on a variety of ships from destroyers to battleships(SONY VGP-BPS13B/Q Battery). Other analog computers included the Heathkit EC-1, and the hydraulic MONIAC Computer which modeled econometric flows.

The art of mechanical analog computing reached its zenith with the differential analyzer, built by H. L. Hazen and Vannevar Bush at MITstarting in 1927(SONY VGP-BPS13Q Battery), which in turn built on the mechanical integrators invented in 1876 by James Thomson and the torque amplifiers invented by H. W. Nieman. A dozen of these devices were built before their obsolescence was obvious; the most powerful was constructed at the University of Pennsylvania's Moore School of Electrical Engineering(SONY Vaio VGN-FW21M Battery), where the ENIAC was built. Digital electronic computers like the ENIAC spelled the end for most analog computing machines, but hybrid analog computers, controlled by digital electronics, remained in substantial use into the 1950s and 1960s, and later in some specialized applications. But like all digital devices(SONY Vaio VGN-FW21L Battery), the decimal precision of a digital device is a limitation, as compared to an analog device, in which the accuracy is a limitation. As electronics progressed during the 20th century, its problems of operation at low voltages while maintaining high signal-to-noise ratios were steadily addressed, as shown below(SONY Vaio VGN-FW21J Battery), for a digital circuit is a specialized form of analog circuit, intended to operate at standardized settings (continuing in the same vein, logic gates can be realized as forms of digital circuits). But as digital computers have become faster and use larger memory (for example, RAM or internal storage) (SONY Vaio VGN-FW21E Battery), they have almost entirely displaced analog computers. Computer programming, or coding, has arisen as another human profession.