Friday, August 29, 2008

Evolution of Computer Systems

Evolution of Computer Systems
Matthew N. O. Sadiku Department of Electrical Engineering Temple University Philadelphia, PA 19122
Although bits and pieces of the historical background on computer systems are found in monographs and encyclopedia, a brief account that a beginner can quickly digest is hard to come by. This article presents such a short account. From ABACUS to ENIAC and from ENIAC to BISDN the paper covers the significant advances associated with computers. It is hoped that the paper is useful to a beginner in the field or an interested non-expert.
Early Developments
The need for counting, computing or processing data has been with man from the beginning. The most significant early computing tool is the ABACUS, a wooden rack holding parallel rods on which beads are strung. This simple device was used for addition and subtraction. A Scottish scholar, John Napier (1550-1617) invented the logarithm and in 1661, William Oughtred invented both the rectilinear and circular slide rules. These are analog computers which have been replaced in modern times by pocket calculators.
A significant advance in the evolution of computing systems was the invention of a mechanical adding machine in 1642 by the French scientist Blaise Pascal (1623-1662). Having observed Pascal's machine in Paris, the German mathematician Gottfried Wilhelm von Leibniz (1646-1716) designed a better one in 1671[1]. While Pascal's machine could only count, Leibniz device could also multiply, divide, and find square root. In 1820, Thomas of Colmar (Charles Xavier Thomas) produced the first commercially available mechanical calculator. This desktop calculator could add, subtract, multiply, and divide. This was followed by a succession of advanced and improved versions of mechanical calculators [2].
While Thomas of Colmar was working on the mechanical calculator, Charles Babbage (1792-1871) at Cambridge, England, was developing the first digital computer. By 1822, he built an automatic mechanical calculator called the "difference engine." In 1833 he
Clarence N. Obiozor Department of Electrical Engineering University of North Florida Jacksonville, FL 32224
began to work on a general-purpose, programmable, automatic mechanical digital computer called the "analytic machine". Unfortunately, Babbage's analytical engine was never completed because its design required fabrication precision beyond what was feasible at that time.
A major step forward in the evolution of computer systems is the invention of punch cards which was first used during the U.S. census of 1890 by Herman Hollerith and James Powers while working for the U.S. Census Bureau. With the punch cards, the calculating machines became fully automatic. In 1896 Hollerith formed the Tabulating Machine Company which manufactured punch card machines. After his retirement in 1913, Thomas J. Watson, Sr. became president of the company, which became International Business Machines Corporation in 1924. This company was later to play a significant role in the evolution of computer systems.
Modern Digital Systems
Although the punched machine was well established and reliable by the late 1930’s, several research groups worked hard to build automatic digital computer. A group of IBM team of four workers led by Howard Hathaway Aiken, a physicist and mathematician at Harvard University, began work on a fully automatic calculator in 1939. The calculator, commonly called the International Business Machines Automatic Sequence Controlled Calculator or Harvard Mark I, was completed in August 1944. This was the first information-processing machine. As an electromechanical computer, it has 760,000 wheels, 500 miles of wire, and a panel 51 ft long and 8ft high. Input data was entered through the punched cards, and the output was by punched card or electric typewriter. Aiken's machine was similar in principle to Babbage's analytical machine although Aiken did not know about Babbage's work when he started his research.
The first all-digital electronic computer made its appearance during the World War II. In the United States, there was the desperate need for computers that
would quickly compute firing tables for the variety of new weapons used by the U.S. army. In 1942, electrical engineer J. Presper Eckert and physicist John W. Mauchly, at the Moore School of Engineering, University of Pennsylvania, Philadelphia, met the need and developed ENIAC (Electronic Numerical Integrator and Calculator). ENIAC went into operation in 1946. It was the first all-purpose, digital electronic computer. It used vacuum tubes instead of relays as the logic elements. Because of this, it was more than 1,000 faster than its electromechanical predecessors. However, ENIAC was of an unprecedented size and complexity.
In 1950, ENIAC was succeeded by EDVAC (Electronic Discrete Variable Automatic Computer), a stored-program computer. In 1947, Eckert and Mauchly established their own company, Eckert-Mauchly Computer Corporation, to manufacture computers commercially. In 1951, the company produced the UNIVAC I (Universal Automatic Computer) for the U.S. Census Bureau. Although this first commercial computer was produced for the Census Bureau, it was used extensively by the scientific community. UNIVAC I achieved the greatest fame among the early digital computers because it was used to predict correctly the presidential election in 1952. The results projected Dwight Eisenhower's election over Adlai Stevenson 45 minutes after the polls closed.
Generations Of Computers
The first generation of computers (1950-1959) used vacuum tubes as their logic elements and ring-shaped ferrite cores as memories. During this period computers were bulky, unreliable, and expensive. These computers include ENIAC, EDVAC, UNIVAC I, UNIVAC II, IBM 702 and 650. The introduction of semiconductor digital elements marked the beginning of the second computer generation in 1959. The second generation was marked by reduced size and cost with increased speed and reliability. Magnetic tape became the principal external storage medium. IBM produced the 709TX system in 1959 and later produced 7094 which dominated the scientific computer market during the period of 1960-1964. Some of the popular second-generation computers were IBM 7000, 1400 series, UNIVAC III, RCA 301 and 501, Honeywell 400 and 800, and NCR
The second-generation computers (1959-1969) were succeeded by the third computer generation (1969-1977), which used integrated circuits. The era of microelectronics started with the invention of the
integrated circuit(IC) in 1958. With the introduction of integrated circuits , it was possible to have hundreds of circuit elements on a tiny silicon chip. Important members of the third generation include the IBM 360 and 370, UNIVAC 1108, RCA 3301, GE 645, Honeywell 200 series, and the DEC PDP-8.
The fourth-generation computers became available in the 1980s when very large-scale integration (VLSI), in which thousands of transistors and other circuit elements are placed on a single chip, became increasingly common. The VLSI technology greatly increased the circuit density.
While the first-, second-, third-generation computers used ferrite core as memory units, the fourth-generation computers used semiconductor devices fabricated by VLSI technology as ultrahigh-access memory units. The drop in cost associated with the size-reduction trend led to the introduction of personal computers for use in office, schools, and homes. Several companies such as IBM, Apple Computer, and Radio Shack, began to produce and market personal computers with enormous success.
The race is now on building the next or "fifth" generation of computers, machines that exhibit artificial intelligence. Thus new generations of computers will involve robotics and computer networks.
Computer Networks
Originally networks were used to connect only mainframe computers. But with the proliferation of inexpensive computer systems and advances in software, the need to network personal computers and other computer peripherals became apparent. Computer networking has been developed at three levels: local area network (LAN) that interconnect computers located within a relative small area such as a college campus; metropolitan area network (MAN) representing LAN technologies optimized for a metropolitan area such as a city; wide area network (WAN) providing communication services over several kilometers, across the nation, or around the globe [3].
The idea of computer networking started in the 1960s when time-sharing services were first available to the public [4]. Early pioneers were General Electric (GE), XEROX, AT &T, IBM government agencies, research laboratories, and universities. ARPANET was built in 1969 by the Advanced Research Projects (ARPA), an arm of the U.S. Department of Defense. It
was a public network connecting several major universities and research institutions. The ARPANET eventually grew into a U.S. backbone network leading to the current Internet. The success of the ARPANET led its primary contractors (Bolt, Beranek, and Newman) to form a commercial network company, TELENET in 1972.
The metropolitan area networks (MANs) are an outgrowth of LANs. The MAN effort started in 1982. The objectives were to provide for interconnection of LANs, bulk data transfer, digitized voice, and video. The fiber distributed data interface (FDDI) proposed by the American National Standard Institute (ANSI) is the most popular MAN. It is a token ring network with fiber optic as its transmission medium.
In the late 1970s, the concept of ISDN was born. The ISDN is regarded as an all-purpose digital network in that it will provide an integrated access that will support a wide variety of applications in a flexible and cost-effective manner. The implementation of ISDN has been slow in actual practice. The ISDN concept has been tried in many nations. The real excitement of ISDN comes about when one considers the capabilities of broadband ISDN (BISDN).
Robotics And Artificial Intelligence
A robot is a reprogrammable, multifunctional manipulator designed to perform functions ordinarily ascribed to human beings [5]. The key word is reprogrammable because it refers to a built-in computer control system. This distinguishes robots from numerically controlled systems that can adapt to new tasks. The "robot age" began in 1954 when George C. Devol, who is regarded as the "father of robot," patented the first manipulator with a playback memory. By the mid-1960s, the race to create intelligent robots with the most accuracy and speed led to the formation of research centers and laboratories in the new field of robotics and its allied field of artificial intelligence. Researchers' aims were to integrate perceptual and problem-solving capabilities into one system, using computers for controllers or brains, TV cameras for vision, and touch sensors for robot grippers. In 1967, General Electric produced a four-legged vehicle. In 1969 and 1970, researchers at Stanford Research Institute (SRI) produced a mobile robot, known as Shakey, which had some vision capability. In 1974, Vicarm Inc. marketed a robot that used a minicomputer for a controller. By the year 1978, there were about 2,500 industrial robots in the United States. 1980 witnessed the establishment of the largest
university laboratory on robotics at Carnegie Mellon University. In the same year, University of Rhode Island demonstrated a prototype robotics vision system.
Early computers were electromechanical at best; they were limited in speed, reliability, and flexibility. Modern digital computers are fast and reliable. Computer systems will continue to find increasing application in every aspect of human activity. As we approach the next century, the most important areas related to computers will be networking and artificial intelligence.
1 M. R. Williams, A History of Computing Technology. Englewood Cliffs, NJ: Prentice Hall, 1985, p. 139.
2 A. Ralston (ed.), Encyclopedia of Computer Science and Engineering. New York: Nostrand Reinhold Co., 1982, 2nd ed., 1982, pp. 532-554.
3 M. N. O. Sadiku and M. Ilyas, Simulation of Local Area Networks. Boca Raton, FL: CRC Press, 1995, pp. 1-2.
4 J. S. Quarterman, The Matrix. Bedford, MA: Digital Press, 1990, pp.137-174.
5 R. D. Klafter et al., Robotic Engineering: An Integrated Approach. Englewood Cliffs, NJ: Prentice Hall, 1989, p. 10.

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