CENTRAL PROCESSING UNIT

The main unit inside the computer is the CPU. This unit is responsible for all events inside the computer. It controls all internal and external devices, performs arithmetic and logic operations.

The operations a microprocessor (also known as a CPU or central processing unit) performs are called the instruction set of this processor. The instruction set determines the machine language for the CPU. The more complicated the instruction set is, the slower the CPU works.

Processors differ from one another by the instruction set. If the same program can run on two different computer brands they are said to be compatible. Programs written for IBM compatible computers will not run on Apple computers because these two architectures are not compatible. There is an exception to this rule. Apple Macintosh with a program SoftPC loaded can run programs written for IBM PC. Programs like SoftPC make one CPU "pretend" to be another. These programs are called software emulators. Although software emulators allow the CPU to run incompatible programs they severely slow down the performance.

The CPU includes the control unit, the arithmetic and logic unit (ALU) and the registers. The control unit directs and controls the activities of the internal and external devices. It interprets the instructions fetched into the computer, determines what data are needed, where they are stored, where to store the results of the operation, and sends the control signals to the devices involved in the execution of the instructions.

The arithmetic and logic unit (ALU) is the part where actual computations take place. It consists of circuits which perform arithmetic operations (e.g. addition, subtraction, multiplication, division) over data received from memory and capable to compare numbers.

While performing these operations the ALU takes data from the temporary storage area inside the CPU named registers. Registers are a group of cells used for memory addressing, data manipulation and processing. Some of the registers are general purpose and some are reserved for certain functions. It is a high-speed memory which holds only data for immediate processing and results of this processing. If these results are not needed for the next instruction, they are sent back to the main memory and registers are occupied by the new data used in the next instruction.

TASKS

1. Give Russian equivalents of the following words and word combinations. Transcribe them.

1. event (n.)

2. control (v.)

3. internal (adj.)

4. external (adj.)

5. microprocessor (n.)

6. determine (v.)

7. compatible (adj.)

8. architecture (n.)

9. software emulator

10. register (n.)

11. execution (n.)

12. actual (adj.)

13. circuit (n.)

14. multiplication (n.)

15. division (n.)

16. purpose (n.)

17. immediate (adj.)

2. Give English equivalents of the following word combinations

3. Find and underline predicate in each sentence.

1. Programs written for IBM compatible computers will not run on Apple computers because these two architectures are not compatible.

2. Apple Macintosh with a program SoftPC loaded can run programs written for IBM PC.

3. The CPU interprets the instructions fetched into the computer.

4. The CPU sends the control signals to the devices involved in the execution of the instructions.

5. The arithmetic and logic unit performs arithmetic operations over data received from memory.

6. The ALU takes data from the temporary storage area inside the CPU named registers.

7. Registers are a group of cells used for memory addressing, data manipulation and processing.

8. If these results are not needed for the next instruction, they are sent back to the main memory and registers are occupied by the new data used in the next instruction.

5. Read and translate the text.

TEXT 3

MEMORY

Information put into a computer must be stored so that the central processing unit can easily access it. This storage area is called the computer memory and is where programs, data, and intermediate results reside while awaiting process­ing.

The memory of a computer consists of the components that provide the storage of information. Originally these components were vacuum tubes; these were soon replaced by little magnetic doughnuts, called cores, which could be magnetized either clockwise or counterclockwise. Once a core was magnetized, the computer could determine in which direction it was magnetized and thus interpret the information stored. Today, the system is essentially the same, although the core has been replaced by a semiconductor component that per­forms the same function more efficiently.

The term for any device that can store information is bit, an abbreviation for binary digit. The system of count­ing by bits is called the binary system. A bit is the smallest unit of storage of a computer and can exist in one of two states, 0 or 1.

Inside the memory, bits are grouped together into what are called words. Computers can have memories that range from a few thousand words to many millions. However, memory size is usually described in terms of the number of characters it can store—a character being a letter, number, or punc­tuation mark. The number of bits required to store one character is called a byte, and memory is usually measured in thousand of bytes or kilobytes. For very large machines the word megabyte, meaning millions of bytes, is often used.

There are two common types of memory: random-access memory (RAM) and read-only memory (ROM). Random access means that the central processor can read infor­mation from or write information into any of the computer's memory locations. A common analogy for a memory location is a mailbox into which information can be inserted or from which it can be retrieved. RAM is where data or programs that have been entered into the computer are stored. Read-only memory or ROM is, as its name implies, only readable. The implication is that information is permanently stored in ROM and can be read or retrieved by the processor whenever needed.

TASKS

1. Give Russian equivalents of the following words and transcribe them.

1. access (v.) (n.)

3. area (n.)

4. intermediate (adj.)

5. reside (v.)

6. vacuum tubes

7. magnetic doughnut

8. core (n.)

9. magnetize (v.)

10. determine (v.)

11. abbreviation (n.)

12. character (n.)

13. analogy (n

3. Form adverbs

easy, original, essential, intermediate, efficient, permanent

4. Find and underline predicate in each sentence.

1. Information put into a computer must be stored so that the central processing unit can easily access it.

2. This storage area is called the computer memory and is where programs, data, and intermediate results reside while awaiting process­ing.

3. The memory of a computer consists of the components that provide the storage of information.

4. Originally these components were vacuum tubes; these were soon replaced by little magnetic doughnuts, called cores, which could be magnetized either clockwise or counterclockwise.

5. Once a core was magnetized, the computer could determine in which direction it was magnetized and thus interpret the information stored.

6. Today, the system is essentially the same, although the core has been replaced by a semiconductor component that per­forms the same function more efficiently.

7. The term for any device that can store information is bit, an abbreviation for binary digit. The system of count­ing by bits is called the binary system.

8. A bit is the smallest unit of storage of a computer and can exist in one of two states, 0 or 1.

9. Inside the memory, bits are grouped together into what are called words.

10. Computers can have memories that range from a few thousand words to many millions.

11. However, memory size is usually described in terms of the number of characters it can store—a character being a letter, number, or punc­tuation mark. 12. The number of bits required to store one character is called a byte, and memory is usually measured in thousand of bytes or kilobytes.

13. For very large machines the word megabyte, meaning millions of bytes, is often used.

14. There are two common types of memory: random-access memory (RAM) and read-only memory (ROM).

15. Random access means that the central processor can read infor­mation from or write information into any of the computer's memory locations.

16. A common analogy for a memory location is a mailbox into which information can be inserted or from which it can be retrieved.

17. RAM is where data or programs that have been entered into the computer are stored.

18. Read-only memory or ROM is, as its name implies, only readable.

19. The implication is that information is permanently stored in ROM and can be read or retrieved by the processor whenever needed.

5. Read and translate the text.

TEXT 4

Date: 2015-01-02; view: 1046