Open Distributed Systems

Open distributed Systems differ from Distributed Operating systems in a fundamental way: The support for distributed <#177#> applications<#177#> is provided by each host in an open way. There is <#178#> middleware<#178#> between the simple communciations facilities that each host provides and the application. This layer ensures a high degree of independence between the underlying system and applications. In this way, the Distributed System Programmer may provide a <#179#> different<#179#> Virtual Machine depending on the requirements of the Application in question. Each Host's Operating System must be supplemented with the toolset adequate for the set of distributed applications that are required for that host to participate. The full set is not required - the application programmer picks and chooses appropriate tools. This has major advantages over monolithic Distributed Operating Systems in terms of performance, management and scalability. Distributed OS provide a common interface to the application regardless of the physical platform, thus supporting homogeneity for the application programmer.

Figure: Distributed Operating System