Evolution of Computer Systems Matthew N. O. Sadiku Clarence N. Obiozor Department of Electrical Engineering Department of Electrical Engineering Temple University University of North Florida Philadelphia, PA 19122 Jacksonville, FL 32224 Abstract began to work on a general-purpose, programmable, automatic mechanical digital computer called the Although bits and pieces of the historical “analytic machine”. Unfortunately, Babbage's analytical background on computer systems are found in engine was never completed because its design required monographs and encyclopedia, a brief account that a fabrication precision beyond what was feasible at that beginner can quickly digest is hard to come by. This time. article presents such a short account. From ABACUS to ENIAC and from ENIAC to BISDN the paper covers the A major step forward in the evolution of computer significant advances associated with computers. It is systems is the invention of punch cards which was first hoped that the paper is useful to a beginner in the field used during the U.S. census of 1890 by Herman Hollerith or an interested non-expert. and James Powers while working for the U.S. Census Bureau. With the punch cards, the calculating machines Early Developments became fully automatic. In 1896 Hollerith formed the Tabulating Machine Company which manufactured punch card machines. After his retirement in 1913, The need for counting, computing or processing Thomas J. Watson, Sr. became president of the company, data has been with man from the beginning. The most which became International Business Machines significant early computing tool is the ABACUS, a Corporation in 1924. This company was later to play a wooden rack holding parallel rods on which beads are significant role in the evolution of computer systems. 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 Modern Digital Systems invented both the rectilinear and circular slide rules. These are analog computers which have been replaced in Although the punched machine was well estab- modern times by pocket calculators. lished and reliable by the late 1930’s, several research groups worked hard to build automatic digital computer. A significant advance in the evolution of computing A group of IBM team of four workers led by Howard systems was the invention of a mechanical adding Hathaway Aiken, a physicist and mathematician at machine in 1642 by the French scientist Blaise Pascal Harvard University, began work on a fully automatic (1623-1662). Having observed Pascal's machine in Paris, calculator in 1939. The calculator, commonly called the the German mathematician Gottfried Wilhelm von International Business Machines Automatic Sequence Leibniz (1646-1716) designed a better one in 1671[1]. Controlled Calculator or Harvard Mark I, was completed While Pascal's machine could only count, Leibniz device in August 1944. This was the first informa- could also multiply, divide, and find square root. In 1820, tion-processing machine. As an electromechanical Thomas of Colmar (Charles Xavier Thomas) produced computer, it has 760,000 wheels, 500 miles of wire, and the first commercially available mechanical calculator. a panel 51 ft long and 8ft high. Input data was entered This desktop calculator could add, subtract, multiply, and through the punched cards, and the output was by divide. This was followed by a succession of advanced punched card or electric typewriter. Aiken's machine and improved versions of mechanical calculators [2]. was similar in principle to Babbage's analytical machine although Aiken did not know about Babbage's work While Thomas of Colmar was working on the when he started his research. mechanical calculator, Charles Babbage (1792-1871) at Cambridge, England, was developing the first digital The first all-digital electronic computer made its computer. By 1822, he built an automatic mechanical appearance during the World War II. In the United calculator called the "difference engine." In 1833 he States, there was the desperate need for computers that would quickly compute firing tables for the variety of integrated circuit(IC) in 1958. With the introduction of new weapons used by the U.S. army. In 1942, electrical integrated circuits , it was possible to have hundreds of engineer J. Presper Eckert and physicist John W. circuit elements on a tiny silicon chip. Important Mauchly, at the Moore School of Engineering, University members of the third generation include the IBM 360 of Pennsylvania, Philadelphia, met the need and and 370, UNIVAC 1108, RCA 3301, GE 645, Honeywell developed ENIAC (Electronic Numerical Integrator and 200 series, and the DEC PDP-8. Calculator). ENIAC went into operation in 1946. It was the first all-purpose, digital electronic computer. It used The fourth-generation computers became available vacuum tubes instead of relays as the logic elements. in the 1980s when very large-scale integration (VLSI), in Because of this, it was more than 1,000 faster than its which thousands of transistors and other circuit elements electromechanical predecessors. However, ENIAC was are placed on a single chip, became increasingly of an unprecedented size and complexity. common. The VLSI technology greatly increased the circuit density. In 1950, ENIAC was succeeded by EDVAC (Electronic Discrete Variable Automatic Computer), a While the first-, second-, third-generation stored-program computer. In 1947, Eckert and Mauchly computers used ferrite core as memory units, the established their own company, Eckert-Mauchly fourth-generation computers used semiconductor devices Computer Corporation, to manufacture computers fabricated by VLSI technology as ultrahigh-access commercially. In 1951, the company produced the memory units. The drop in cost associated with the UNIVAC I (Universal Automatic Computer) for the U.S. size-reduction trend led to the introduction of personal Census Bureau. Although this first commercial computers for use in office, schools, and homes. Several computer was produced for the Census Bureau, it was companies such as IBM, Apple Computer, and Radio used extensively by the scientific community. UNIVAC I Shack, began to produce and market personal computers achieved the greatest fame among the early digital with enormous success. computers because it was used to predict correctly the presidential election in 1952. The results projected The race is now on building the next or "fifth" Dwight Eisenhower's election over Adlai Stevenson 45 generation of computers, machines that exhibit artificial minutes after the polls closed. intelligence. Thus new generations of computers will involve robotics and computer networks. Generations Of Computers Computer Networks The first generation of computers (1950-1959) used vacuum tubes as their logic elements and ring-shaped Originally networks were used to connect only ferrite cores as memories. During this period computers mainframe computers. But with the proliferation of were bulky, unreliable, and expensive. These computers inexpensive computer systems and advances in software, include ENIAC, EDVAC, UNIVAC I, UNIVAC II, IBM the need to network personal computers and other 702 and 650. The introduction of semiconductor digital computer peripherals became apparent. Computer elements marked the beginning of the second computer networking has been developed at three levels: local area generation in 1959. The second generation was marked network (LAN) that interconnect computers located by reduced size and cost with increased speed and within a relative small area such as a college campus; reliability. Magnetic tape became the principal external metropolitan area network (MAN) representing LAN storage medium. IBM produced the 709TX system in technologies optimized for a metropolitan area such as a 1959 and later produced 7094 which dominated the city; wide area network (WAN) providing scientific computer market during the period of communication services over several kilometers, across 1960-1964. Some of the popular second-generation the nation, or around the globe [3]. computers were IBM 7000, 1400 series, UNIVAC III, RCA 301 and 501, Honeywell 400 and 800, and NCR The idea of computer networking started in the 315. 1960s when time-sharing services were first available to the public [4]. Early pioneers were General Electric The second-generation computers (1959-1969) (GE), XEROX, AT &T, IBM government agencies, were succeeded by the third computer generation research laboratories, and universities. ARPANET was (1969-1977), which used integrated circuits. The era of built in 1969 by the Advanced Research Projects microelectronics started with the invention of the (ARPA), an arm of the U.S. Department of Defense. It was a public network connecting several major university laboratory on robotics at Carnegie Mellon universities and research institutions. The ARPANET University. In the same year, University of Rhode Island eventually grew into a U.S. backbone network leading to demonstrated a prototype robotics vision system. the current Internet. The success of the ARPANET led its primary contractors (Bolt, Beranek, and Newman) to Conclusion form a commercial network company, TELENET in 1972. Early computers were electromechanical at best; they were limited in speed, reliability, and flexibility. The metropolitan area networks (MANs) are an Modern digital computers are fast and reliable. Computer outgrowth of LANs. The MAN effort started