Computer

A

Early Electronic Calculators

Herman Hollerith, an American inventor, used an idea similar to Jacquard’s loom when he combined the use of punched cards with devices that created and electronically read the cards. Hollerith’s tabulator was used for the 1890 U.S. census, and it made the computational time three to four times shorter than the time previously needed for hand counts. Hollerith’s Tabulating Machine Company eventually merged with two companies to form the Computing-Tabulating-Recording Company. In 1924 the company changed its name to International Business Machines (IBM).

In 1936 British mathematician Alan Turing proposed the idea of a machine that could process equations without human direction. The machine (now known as a Turing machine) resembled an automatic typewriter that used symbols for math and logic instead of letters. Turing intended the device to be a “universal machine” that could be used to duplicate or represent the function of any other existing machine. Turing’s machine was the theoretical precursor to the modern digital computer. The Turing machine model is still used by modern computational theorists.

In the 1930s American mathematician Howard Aiken developed the Mark I calculating machine, which was built by IBM. This electronic calculating machine used relays and electromagnetic components to replace mechanical components. In later machines, Aiken used vacuum tubes and solid state transistors (tiny electrical switches) to manipulate the binary numbers. Aiken also introduced computers to universities by establishing the first computer science program at Harvard University in Cambridge, Massachusetts. Aiken obsessively mistrusted the concept of storing a program within the computer, insisting that the integrity of the machine could be maintained only through a strict separation of program instructions from data. His computer had to read instructions from punched cards, which could be stored away from the computer. He also urged the National Bureau of Standards not to support the development of computers, insisting that there would never be a need for more than five or six of them nationwide.

B

EDVAC, ENIAC, and UNIVAC

At the Institute for Advanced Study in Princeton, New Jersey, Hungarian-American mathematician John von Neumann developed one of the first computers used to solve problems in mathematics, meteorology, economics, and hydrodynamics. Von Neumann's 1945 design for the Electronic Discrete Variable Automatic Computer (EDVAC)—in stark contrast to the designs of Aiken, his contemporary—was the first electronic computer design to incorporate a program stored entirely within its memory. This machine led to several others, some with clever names like ILLIAC, JOHNNIAC, and MANIAC.

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American physicist John Mauchly proposed the electronic digital computer called ENIAC, the Electronic Numerical Integrator And Computer. He helped build it along with American engineer John Presper Eckert, Jr., at the Moore School of Engineering at the University of Pennsylvania in Philadelphia. ENIAC was operational in 1945 and introduced to the public in 1946. It is regarded as the first successful, general digital computer. It occupied 167 sq m (1,800 sq ft), weighed more than 27,000 kg (60,000 lb), and contained more than 18,000 vacuum tubes. Roughly 2,000 of the computer’s vacuum tubes were replaced each month by a team of six technicians. Many of ENIAC’s first tasks were for military purposes, such as calculating ballistic firing tables and designing atomic weapons. Since ENIAC was initially not a stored program machine, it had to be reprogrammed for each task.

Eckert and Mauchly eventually formed their own company, which was then bought by the Rand Corporation. They produced the Universal Automatic Computer (UNIVAC), which was used for a broader variety of commercial applications. The first UNIVAC was delivered to the United States Census Bureau in 1951. By 1957, there were 46 UNIVACs in use.

Between 1937 and 1939, while teaching at Iowa State College, American physicist John Vincent Atanasoff built a prototype computing device called the Atanasoff-Berry Computer, or ABC, with the help of his assistant, Clifford Berry. Atanasoff developed the concepts that were later used in the design of the ENIAC. Atanasoff’s device was the first computer to separate data processing from memory, but it is not clear whether a functional version was ever built. Atanasoff did not receive credit for his contributions until 1973, when a lawsuit regarding the patent on ENIAC was settled.

XIII

The Transistor and Integrated Circuits Transform Computing

In 1948, at Bell Telephone Laboratories, American physicists Walter Houser Brattain, John Bardeen, and William Bradford Shockley developed the transistor, a device that can act as an electric switch. The transistor had a tremendous impact on computer design, replacing costly, energy-inefficient, and unreliable vacuum tubes.

In the late 1960s integrated circuits (tiny transistors and other electrical components arranged on a single chip of silicon) replaced individual transistors in computers. Integrated circuits resulted from the simultaneous, independent work of Jack Kilby at Texas Instruments and Robert Noyce of the Fairchild Semiconductor Corporation in the late 1950s. As integrated circuits became miniaturized, more components could be designed into a single computer circuit. In the 1970s refinements in integrated circuit technology led to the development of the modern microprocessor, integrated circuits that contained thousands of transistors. Modern microprocessors can contain more than 40 million transistors.

Manufacturers used integrated circuit technology to build smaller and cheaper computers. The first of these so-called personal computers (PCs)—the Altair 8800—appeared in 1975, sold by Micro Instrumentation Telemetry Systems (MITS). The Altair used an 8-bit Intel 8080 microprocessor, had 256 bytes of RAM, received input through switches on the front panel, and displayed output on rows of light-emitting diodes (LEDs). Refinements in the PC continued with the inclusion of video displays, better storage devices, and CPUs with more computational abilities. Graphical user interfaces were first designed by the Xerox Corporation, then later used successfully by Apple Inc.. Today the development of sophisticated operating systems such as Windows, the Mac OS, and Linux enables computer users to run programs and manipulate data in ways that were unimaginable in the mid-20th century.

Several researchers claim the “record” for the largest single calculation ever performed. One large single calculation was accomplished by physicists at IBM in 1995. They solved one million trillion mathematical subproblems by continuously running 448 computers for two years. Their analysis demonstrated the existence of a previously hypothetical subatomic particle called a glueball. Japan, Italy, and the United States are collaborating to develop new supercomputers that will run these types of calculations 100 times faster.

In 1996 IBM challenged Garry Kasparov, the reigning world chess champion, to a chess match with a supercomputer called Deep Blue. The computer had the ability to compute more than 100 million chess positions per second. In a 1997 rematch Deep Blue defeated Kasparov, becoming the first computer to win a match against a reigning world chess champion with regulation time controls. Many experts predict these types of parallel processing machines will soon surpass human chess playing ability, and some speculate that massive calculating power will one day replace intelligence. Deep Blue serves as a prototype for future computers that will be required to solve complex problems. At issue, however, is whether a computer can be developed with the ability to learn to solve problems on its own, rather than one programmed to solve a specific set of tasks.

XIV

The Future of Computers

In 1965 semiconductor pioneer Gordon Moore predicted that the number of transistors contained on a computer chip would double every year. This is now known as Moore’s Law, and it has proven to be somewhat accurate. The number of transistors and the computational speed of microprocessors currently doubles approximately every 18 months. Components continue to shrink in size and are becoming faster, cheaper, and more versatile.

With their increasing power and versatility, computers simplify day-to-day life. Unfortunately, as computer use becomes more widespread, so do the opportunities for misuse. Computer hackers—people who illegally gain access to computer systems—often violate privacy and can tamper with or destroy records. Programs called viruses or worms can replicate and spread from computer to computer, erasing information or causing malfunctions. Other individuals have used computers to electronically embezzle funds and alter credit histories (see Computer Security). New ethical issues also have arisen, such as how to regulate material on the Internet and the World Wide Web. Long-standing issues, such as privacy and freedom of expression, are being reexamined in light of the digital revolution. Individuals, companies, and governments are working to solve these problems through informed conversation, compromise, better computer security, and regulatory legislation.

Computers will become more advanced and they will also become easier to use. Improved speech recognition will make the operation of a computer easier. Virtual reality, the technology of interacting with a computer using all of the human senses, will also contribute to better human and computer interfaces. Standards for virtual-reality program languages—for example, Virtual Reality Modeling language (VRML)—are currently in use or are being developed for the World Wide Web.

Other, exotic models of computation are being developed, including biological computing that uses living organisms, molecular computing that uses molecules with particular properties, and computing that uses deoxyribonucleic acid (DNA), the basic unit of heredity, to store data and carry out operations. These are examples of possible future computational platforms that, so far, are limited in abilities or are strictly theoretical. Scientists investigate them because of the physical limitations of miniaturizing circuits embedded in silicon. There are also limitations related to heat generated by even the tiniest of transistors.

Intriguing breakthroughs occurred in the area of quantum computing in the late 1990s. Quantum computers under development use components of a chloroform molecule (a combination of chlorine and hydrogen atoms) and a variation of a medical procedure called magnetic resonance imaging (MRI) to compute at a molecular level. Scientists use a branch of physics called quantum mechanics, which describes the behavior of subatomic particles (particles that make up atoms), as the basis for quantum computing. Quantum computers may one day be thousands to millions of times faster than current computers, because they take advantage of the laws that govern the behavior of subatomic particles. These laws allow quantum computers to examine all possible answers to a query simultaneously. Future uses of quantum computers could include code breaking (see cryptography) and large database queries. Theorists of chemistry, computer science, mathematics, and physics are now working to determine the possibilities and limitations of quantum computing.

Communications between computer users and networks will benefit from new technologies such as broadband communication systems that can carry significantly more data faster or more conveniently to and from the vast interconnected databases that continue to grow in number and type.

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