1. The time required for the computer to locate and transfer
data in the storage device is called the data____ time.
a) sequence; b) access; c) value
2.______ memories have no moving parts.
a) electronic; b) mechanical; c) electromechanical
3. Magnetic______ were the main elements used for pri
mary memory in digital computers for many years.
a) cores; b) tapes; c) disks
4.______ is more commonly used for memory at present.
a) bipolar semiconductor; b) MOS; c) field-effect transistor
5. Magnetic disks constitute the_____ storage media.
a) internal; b) primary; c)secondary
6. Data are stored in______ codes in primary as well as in
secondary storage.
a) digital; b) binary; c) numerical
7. Data access time is_____ in electronic memories than
that in electromechanical memories.
a) longer; b) much longer; c) shorter
8. Electronic memories have____ capacities for data stor-
age.
a) more; b) larger; c) less
97 Unit 7. Storage
2. , .
1. Primary a) one of the performance characteris-
tics of storage measured in binary digits;
2. Secondary b) memory that has random access to
the information;
3. Magnetic disc c) combination of units of information;
4. Binary codes d) the main method of secondary stor-
age performing both sequential and random storage;
5. RAM e) area of memory where protected pro-
grams can be read from but not written on;
6. Bit f) a fixed number of consecutive bits
representing a character;
7. Byte g) the principal flexible second storage
circuit element;
8. ROM h) part of memory having lower speed
but greater capacity;
9. Floppy i) a unit of information or binary digit;
10. Capacity. j) the most expensive part of memory
having the least capacity and the fastest access time.
Unit 8 CENTRA L PROCESSING UNIT
1 1.
central processing unit (CPU) -
()
interchangeably [,mt3'tfemd33bli] -
precisely [pn'saish]
internal memory - ; activity [sk'tiviti] - ; ; to issue ['isju:] - (); ,
() response [n'spons] - ; ; ; ;
to interprete [m'tspnt] - ; ;
according to [a'bdin ts] - ; level - ; ; ; input-output port - - control unit (CU) [bn'troul 'ju:nit] - arithmetic-logical unit (ALU) - -
switch ['switJl - ; ; ; direct [di'rekt] - ; ; ;
; step-by-step operations - to select [ss'lekt] - ; ( ) on the other hand - exponentiation [ekspe'nenji'eifn] -
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99 Unit 8. Central Processing Unit
call for ;
to load ['loud] ;
2. , .
Text 1. CENTRAL PROCESSING UNIT
It is well known in computer science that the words 'computer' and 'processor' are used interchangeably. Speaking 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.
The CPU coordinates all the activities of the various components of the computer. It determines which operations should be carried out and in what order. The CPU controls the operation of the entire system by issueing commands to other parts of the system and by acting on responses. When required it reads information from the memory, interprets instructions, performs operations on the data according to the instructions, writes the results back into the memory and moves information between memory levels or through the input-output ports.
In4igital computers the CPU can be divided into two functional units called the control unit (CU) and the arithmetic-logical unit (ALU). These two units are made up of electronic circuits with millions of switches that can be in one of two states, either on or off.
The function of the CU within the central processor is to transmit coordinating control signals and commands. The control unit is that part of the computer that directs the sequence of step-by-step operations of the system, selects instructions and data from memory, interprets the program instructions, and controls the flow between main storage and the arithmetic-logical unit.
The ALU, on the other hand, is that part of the computer in which the actual arithmetic operations, namely, addition, subtraction* multiplication, division and exponentiation, called for in the instructions are performed.
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Programs and the data on which the CU and the ALU operate, must be in internal memory in order to be processed. Thus, if located in secondary memory devices, such as disks or tapes, programs and data are first loaded into internal memory.
3. . ,
.
1. What words in computer science are used interchangeably and why? 2. What components make up the heart of the computer system. 3. What is the function of the CPU? 4. In what way does the CPU control the operation of the whole system? 5. Name the sequence of operations the CPU performs (use five verbs). 6. What are the CPU functional units made of? 7. What is the function of the CU? 8. What operations are performed in the ALU? 9. Where are data processed? 10. Where are data to be processed loaded into?
4.
:
; ; ; ; ; ; ; ; ; ; ; -; ; ; ; ; ; -
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101 Unit 8. Central Processing Unit
; ; , , , , ; .
