TABLE OF CONTENTS The first major step toward computer system compatibility was the development of the OSI Reference Model in the early 1980s. Developed by the International Organization for Standardization (ISO), the OSI Reference Model was the first step towards organizing the problem of end-to-end network compatibility. While it did not provide a very useful mechanism for developing actual products, OSI provided a standard framework and vocabulary for defining and addressing compatibility issues.
The first step in establishing compatibility is to organize and define the overall task; in OSI, this is done by means of a layered model. To construct the model, the entire job of data networking is broken down into a series of tasks that are then assembled into logical groupings, each logical grouping becoming a layer in the model. The OSI Reference Model defines seven layers or groups of tasks that must be addressed. In order for two devices to communicate, they must be compatible at all seven layers.
It is important to note that the OSI Model is not a protocol, but rather a definition of functions to be provided by protocols. The OSI Reference Model sets out what functions must be accomplished at each layer so that protocols could be developed to define exactly how those tasks are performed. So rather than actually making things compatible, the OSI model describes how the job of arranging compatibility should be...
