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Books and References © Rance Necaise |
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Copyright © 2021
by Rance Necaise |
Chapter 1
Introduction
Modern computers contain processors that are implemented using integrated circuits through which electrical currents flow. Computations are performed and decisions are made as the electricity flows through the circuits. The data used in these operations is stored in the memory of the computer, which is also constructed using integrated circuits. Computer organization deals with how these circuits are constructed and the signals used to control the flow of electricity through the circuits. Basically, it involves all physical aspects of a computer system. The study of computer architecture, on the other hand, deals with an abstract model or the programmer's view of the computer system. It involves many different aspects or elements of the system. Some of which include the instruction sets and formats, operation codes, data types, the number and types of registers, addressing modes, memory access, and various I/O operations. Two computers can have the same architecture but have different organizations. For example, both Intel and Advanced Micro Devices (AMD) both make processors that implement the x86 instruction set architecture, but they are implemented in different ways. This means they can both run the same executable programs, but the circuits work in different ways to accomplish the same task. On the other hand, the ARM (Advanced RISC Machines) processors, which are used on more than 95% of mobile phones, has a different architecture than the x86 processors. Thus, a program that can execute on the x86 processors can not be used on an ARM processor and vice versa. There is no clear-cut distinction between computer organization and computer architecture as neither area can stand alone without the other. Even professionals in the areas of computer science and computer engineering have different opinions as to which concepts belong to computer organization and which belong to computer architecture. None the less, we can say that computer architecture describes "what" the computer does while computer organization describes "how" the computer does it.
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