FUNCTIONAL UNITS OF DIGITAL COMPUTERS
As we know, all computer operations can be grouped into five functional categories. The method in which these five functional categories are related to one another represents the functional organization of a digital computer. By studying the functional organization, a broad view of the computer is received.
The five major functional units of a digital computer are:
1) Input to insert outside information into the machine;
2) Storage or memory to store information and make it avail
able at the appropriate time;
3)Arithmetic-logical unit to perform the calculations;
4) Output to remove data from the machine to the outside world and
5) Control unit to cause all parts of a computer to act as a team.
Figure 5 shows how the five functional units of the computer act together. A complete set of instructions and data are usually fed through the input equipment to the memory where they are stored. Each instruction is then fed to the control unit. The control unit interprets the instructions and issues commands to the other functional units to cause operations to be performed on the data. Arithmetic operations are performed in the arithmetic-logical unit, and the results are then fed back to the memory. Information may be fed from either the arithmetic unit or the memory through the output equipment to the outside world. The five units of the computer must communicate with each other. They can do this by means of a machine language which uses a code composed of combinations of electric pulses. These pulse combinations are usually represented by zeros and ones, where the one may be a pulse and the zero a no-pulse. Numbers are communicated between one unit and another by means of these one-zero or pulse no-pulse combinations. The input has the additional job of converting the information fed in by the operator into machine language. In other words, it translates from our language into the pulse no-pulse combinations understandable to the computer. The output's additional job is converting the pulse no-pulse combinations into a form understandable to us, such as a printed report.
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1. What represents the functional organization of a computer? 2. What can we get by studying the functional organization? 3. What is the function of the input device? 4. What does memory serve for? 5. What is the task of the arithmetic-logical unit? 6. What is the function of the output? 7. What is the main pur
pose of the control unit? 8. How do all units of the computer
communicate with each other? 9. What is the additional job of
the input? 10. What is the additional function of the output?
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Organization, functional, available, equipment, processor, completely, architectural, converter, convertible, controller, removable, logical, addition, additional, usually, accomplishment, operator, operation, mainly, communication, insertion, electronic, digital, instruction, generally, arithmetic, daily", development, central, lately, visible, substitution, understandable.
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Computer, analog computer; digital computer; hybrid computer; all-purpose computer; general-purpose computer; fifth-generation computer; game computer; handheld computer; mobile computer; multimedia computer; notebook computer; pocket computer; portable computer.
Unit: unit of memory; unit of data; unit of measurement; arithmetic unit; arithmetic-logical unit; central processing unit; computing unit; control unit; functional unit; input unit; output unit; network unit; system unit.
Function: arithmetic function; checking function; complex function; computer function; continuous function; conversion function; distribution function; encoding function; logical function; numeric function; output function; program function; search function; software function; support function; utility function; variable function.
Control: access control; batch control; coding control; distance / remote control; error control; execution control; hardware control; input/output control; memory control; power control; production control; program control; rate control; self-acting control; software control; system control.
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A. Small; fast; new; long; late; wide; young; easy; great; dull;
rich; bulky; large; vast; early; old; broad.
B. Frequent; reliable; approximate; significant; intricate;
possible; basic; remarkable; common; modern; dependent; general; necessary; successful; scientific; universal.
Good; bad; little; many.
