WHAT IS A MICROPROCESSOR?

1. A microprocessor is a programmable logic device. That is, the function or logical operation that the device performs may be changed by applying instructional "words" at its input. Technically, the term microprocessor has come to mean the central arithmetic and logic unit of a computer, together with its associated circuitry, scaled down so that it fits on a single silicon chip (sometimes several chips) holding tens of thousands of transistors, resistors and similar circuit elements. It is a member of the family of large-scale integrated circuits that reflect the present state of evolution of a miniaturization process that began with the development of the transistor in the late 1940's.

2. The first microprocessors were developed in 1971 as a branch of pocket calculator development. Since then there has been a tremendous increase of work in this field and some years later there appeared dozens of different microprocessors commercially available.

3. A typical microprocessor chip measures half a centimeter on a side. By adding anywhere from 10 to 80 chips to provide timing program memory, random-access memory (RAM), interfaces for input and output signals and other additional devices one can assemble a complete computer system on a board whose area does not exceed the size of this page. Such an assembly is a microcomputer, in which the microprocessor serves as the master component. The number of applications for microprocessors is increasing daily in industry, in banking, in power generation and distribution, in telecommunication and in different consumer products ranging from automobiles to electronic games.

4. As in the central processing unit or CPU, of a larger computer, the task of the microprocessor is to receive data in the form of strings of binary digits (O's and l's), to store the data for later processing, to perform arithmetic and logic operations on the data in according to the previously stored instructions and to deliver the results to the user through an output mechanism such as an electric typewriter, a cathode-ray-tube display or a two-dimensional plotter.

5. A typical microprocessor consists of the following units: a decode and control unit (to interpret instructions from the stored program), the arithmetic and logic unit, or ALU (to perform arithmetic and logic operations), registers (to serve as an easily accessible memory for data frequently manipulated), an accumulator (a special register closely associated with the ALU), address buffers (to supply the control memory with the address from which to take the next instruction) and input-output buffers (to read instructions or data into the microprocessor or to send them out).

6. The age of the microprocessor is not great. Yet, we have seen the evolution of the microprocessor as it progressed from early applications in simple hand-held calculators through 4- and 8-bit controller applications towards more sophisticated processing operations.

7. Present microprocessors vary in their detailed architecture depending on their manufacture and on the particular semiconductor technology applied. The elements of the microprocessor are divided among several identical modular chips linked in parallel. The total number of chips depends on the length of the "word" the user wants to process: 4 bits (binary digits), 8 bits, 16 bits, or more. Such a multichip arrangement is known as a bit-sliced organization. 8-bit microcomputers usually support only one user terminal and have a maximum of 64 KB of memory. 16-bit microcomputers may support several user terminals and usually have a maximum of 1 million bytes of memory. New micros work with 32-bit word lengths and can access 1 Mbytes of main memory. Minicomputers are 16- or 32-bit machines and can access 16 Mbytes of main memory. As the power of microcomputers increases, they can be used in two ways. They can be used either as a central computer (providing processing for several user terminals), or as a more powerful single computer for an individual user.

8. The terms “microcomputer” and “microprocessor” can be used interchangeably when reffering to the whole system. But there is a significant difference between them. The word "processor" usually refers to the central part of the system only. So a microprocessor is also a central processing part of a microcomputer. The term "computer" refers to a complete system of which a processor is a part. So microcomputer contains a microprocessor plus additional circuitry needed to complete the system.

Notes:

1. plotter - графовибудовувач

2. accessible = available – доступний

3. innovation - нововведения, інновація

4. sophisticated – складний, тонкий (про прилад, пристрій i т.п.)

5. to decrease = to reduce – зменшувати

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	\|	Ex. 8. Find in the text English equivalents to the following words and word-combinations.

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