UNIT 7
I. Look up in the dictionary how to pronounce the following words. Write them down in the dictionary.
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interchangeably to retrieve a reference |
a portion a flow a counter |
a decoder timing marks a bank |
a bistable device an adder
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II. Read the text and do the exercises that follow it.
The Central Processing Unit and Arithmetical Logical Unit.(CPU and ALU)
It is common practice in computer science for the words ‘computer’ and ‘processor’ to be used interchangeably. More precisely, ‘computer’ refers to the central processing unit (CPU) together with an internal memory. The internal memory, control and processing components make up the heart of the computer system. Manufactures design the CPU to control and carry out basic instructions for their particular computer.
In digital computers the CPU can be divided into two functional units called the control unit (CU) and the arithmetical-logical unit (ALU). These two units are made up of electronic circuits with millions of switches that can be one of two states, either on or off.
The function of the control unit within the central processor is to transmit coordinating control signals and commands. The control unit is that portion of the computer that directs the sequence or step-by-step operation of the system, selects instructions and data from memory, interprets the program instructions, and controls the flow between main storage and the arithmetical-logical unit.
A control unit has the following components:
a) a counter that selects the instructions, one at a time, from the memory;
b) a register that temporarily holds the instruction read from memory while it is being executed;
c) a decoder that takes the called instruction and breaks it down into individual commands necessary to carry it out;
d) a clock, which while not a clock in the sense of a time-keeping device, does produce marks at regular intervals.
This timing marks are electronic and very rapid.
The arithmetical-logical unit (ALU) is that portion of the computer in which the arithmetical operations, namely, addition, subtraction, multiplication, division and exponentiation, called for in the instructions are performed.
Programs and the data on which the control unit and the ALU operate, must be in internal memory in order to be processed. Thus, if located on secondary memory devices such as disks or tapes, programs and data are first loaded into internal memory.
The primary components of the ALU are banks of bistable devices, which are called register. Their purpose is to hold the numbers involved in the calculation and hold the result temporarily unit they can be transferred to memory.
At the core of the arithmetical-logical unit is a very high-speed binary adder, which is used to carry out at last the four basic arithmetical functions (addition, subtraction, multiplication and division).
Typical modern computers can perform as many as one hundred thousand additions of pairs of thirty-two binary numbers within a second.
The logical unit consists of electronic circuitry, which compares information and makes decisions based upon the result of the comparison. The decisions that can be made are whether a number is greater than, equal to, or less than another number.
III. Find English equivalents in the text:
1. более точно
2. внутренняя память
3. управлять и обрабатывать
4. сердце компьютерной системы
5. выполнять основные инструкции
6. миллионы переключателей
7. передавать контрольные сигналы
8. часть компьютера
9. счетчик, который выбирает инструкции
10. временно удерживать
11. переделывать (переводить) инструкции в индивидуальные команды
12. устройство, которое показывает время
13. возведение в степень
14. загружать
15. бистабильное устройство
16. сравнивание
IV. Give Russian equivalents to the following words and expressions:
1. common practice
2. to be used
3. manufactures design the CPU
4. can be divided into two functional units
5. are made up of electronic circuits
6. to transmit coordinating control signals
7. the sequence or step-by-step operation
8. to interpret the program instructions
9. the flow between main storage and the ALU
10. one at a time
11. is being executed
12. rapid
13. in order to be processed
14. secondary memory device
15. involved
16. within a second
V. Give the situations from the text in which the following words and expressions are used:
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1. the words computer and processor 2. the internal memory 3. the function of control unit 4. components 5. the arithmetical-logical unit |
6. located 7. first loaded 8. primary components 9. high-speed binary adder 10. electronic circuitry |
VI. Fill in the blanks necessary words and prepositions:
1. More precisely, ‘computer’ refers ..... the central processing unit.
2. The CPU can also ..... information from memory and can ..... the result of manipulations back into ..... unit ..... later reference.
3. The control unit is that portion of the computer that ..... the sequence operations of the system, selects ..... and data ..... memory and controls the flow ..... main storage and the ALU.
4. Programs and the data on which the control unit and the ALU operate, must be in ..... to be processed.
5. At the core of the arithmetical-logical unit is a very high-speed.
6. Modern computers can ..... more than one hundred thousand additions ..... thirty-two bits within a second.
7. It is common practice in computer science ..... the words ‘computer’ and ‘processor’ to be used.
VII. Find in the text synonyms to the following words:
VIII. Find in the text antonyms to the following words:
IX. Answer the following questions:
1. Where does the word ‘computer’ refer to?
2. How can the CPU in digital computers be divided?
3. What is the function of the control unit?
4. What components has a control unit?
5. What is the arithmetical-logical unit?
6. Where are programs and data first loaded?
7. What are the primary components of the ALU?
8. What can modern computers perform?
X. Retell the text in English.