Unit 10. Fiber Optic Cable

Very thin transparent fibers have been developed that will eventually replace the twisted-pair copper wire traditionally used in the telephone system. These hairlike fiber optic cables carry data faster and are lighter and less expensive than their copper-wire counterparts. Twisted-pair wire and coaxial cable carry data as electrical signals. Fiber optic cable carries data as laser-generated light beams.

The differences between the data transmission rates of copper wire and fiber optic cable are tremendous. In the time it takes to transmit a single page of Webster’s Unabridged Dictionary over twisted-pair copper wire (about 6 seconds), the entire dictionary could be transmitted over a single fiber optic cable.

Another of the many advantages of fiber optic cable is its contribution to data security. It is much more difficult for a computer criminal to intercept a signal sent over fiber optic cable (via a beam of light) than it is over copper wire (an electrical signal).

Fiber optic technology has opened the door for some very interesting domestic applications. The high-capacity cable will service our telephone, our TV, and our PC. Fiber optic cable will unable us to see the party on the other end of the telephone conversation. As for TV viewing, we will be able to choose from hundreds of movies, including current releases, and we will be able to choose when we watch them. In the PC world, tapping into an information network will be an increasingly visual experience, with plenty of high-resolution color graphics. For example, instead of reading a buying service’s product description, we’ll be able to view a photo-quality display of it. However, we may need to wait a few years to enjoy these services. The expense of fiber optic cable may delay its wide-spread implementation in the home.

Texts for independent class and home translation Text 1. Computer science

Computer science is a field of study that deals with the structure, operation, and application of computers and computer systems.

Computer science includes engineering activities, such as the design of computers and of the hardware and software of computer systems, and theoretical, mathematical activities, such as the analysis of algorithms and performance studies of systems. It also involves experimentation with new computer systems and their potential applications.

Computer science was established as a discipline in the early 1960s. Its roots lie mainly in the fields of mathematics (e.g., Boolean algebra) and electrical engineering (e.g., circuit design). The major subdisciplines of computer science are (1) architecture (the design and study of computer systems), an area that overlaps extensively with computer engineering; (2) software, including such topics as software engineering, programming languages, operating systems, information systems and databases, artificial intelligence, and computer graphics; and (3) theory, including computational methods and numerical analysis as well as data structures and algorithms.

Text 2. Computer

Computer is any of various automatic electronic devices that solve problems by processing data according to a prescribed sequence of instructions. Such devices are of three general types: analog, digital, and hybrid. They differ from one another in terms of operating principle, equipment design and application.

The analog computer operates on data represented by continuously variable quantities, such as angular positions or voltages, and provides a physical analogy of the mathematical problem to be solved. Capable of solving ordinary differential equations, it is well suited for use in systems engineering, particularly for implementing real-time simulated models of processes and equipment. Another common application is the analysis of networks, such as those for electric-power distribution.

Unlike the analog computer, which operates on continuous variables, the digital computer works with data in discrete form — i.e., expressed directly as the digits of the binary code. It counts, lists, compares, and rearranges these binary digits, or bits, of data in accordance with very detailed program instructions stored within its memory. The results of these arithmetic and logic operations are translated into characters, numbers, and symbols that can be readily understood by the human operator or into signals intelligible to a machine controlled by the computer. Digital computers can be programmed to perform a host of varied tasks. As a consequence, more than 90 percent of the computers in use today are of this type. Government and business make extensive use of the digital computer's ability to organize, store, and retrieve information by setting up huge data files. Its capacity to adjust the performance of systems or devices without human intervention also lends itself to many applications. For example, the digital computer is used to control various manufacturing operations, machine tools, and complex laboratory and hospital instruments. The same capability has been exploited to automate the operational systems of high-performance aircraft and spacecraft. Among the multitude of other significant applications of the digital computer are its use as a teaching aid (e.g., in the remedial instruction of basic language and mathematics skills) and its employment in scientific research to analyze data and generate mathematical models.

The hybrid computer combines the characteristics and advantages of analog and digital systems; it offers greater precision than the former and more control capability than the latter. Equipped with special conversion devices, it utilizes both analog and discrete representation of data. In recent years hybrid systems have been used in simulation studies of nuclear-power plants, guided-missile systems, and spacecraft, in which a close representation of a dynamic system is essential.

Mechanical analog and digital computing devices date back to the 17th century. A logarithmic calculating device, which was the precursor of the slide rule and is often regarded as the first successful analog device, was developed in 1620 by Edmund Gunter, an English mathematician. The first mechanical digital calculating machine was built in 1642 by the French scientist-philosopher Blaise Pascal. During the ensuing centuries, the ideas and inventions of many mathematicians, scientists, and engineers paved the way for the development of the modern computer.

The direct forerunners of present-day analog and digital systems emerged about 1940. John V.Atanasoff built the first electronic digital computer in 1939. Howard Aiken's fully automatic large-scale calculator using standard machine components was completed in 1944. J. Presper Eckert and John W. Mauchly completed the first programmed general-purpose electronic digital computer in 1946. The first stored-program computers were introduced in the late 1940s, and subsequent computers have increasingly become faster and more powerful.