In this series: Practical Framework for the FOSS Bill, Desktops, Small Servers, and Large Integrated Systems
Things become more interesting and more complicated when we get to large integrated systems. This is the realm of "big iron", the mainframes and the UNIX servers of this world. And if you have to ask: in this PC-dominated world, are they still necessary? the answer is yes.
These systems are needed when there's a tremendous amount of data that needs to be processed, or when the processing is complex, or when several processes take place simultaneously. Some data services are so critical they need "hot sites", and sometimes these require such large systems. Finally, these systems may be employed in server consolidation efforts -- when there are too many small servers, it may be cheaper to run them as virtual machines within large servers.
Clearly, large servers represent the major exception in government IT systems. The good news: many of them can run FOSS OSes, either natively or as virtual machines. The bad news: the FOSS OSes running on these systems may not work as well as their native OSes. The good news: the OS might not really matter as these systems can run FOSS software.
It's also in these large integrated systems that applications tend to matter most. These are either complex packaged applications or heavily customized applications. We'll tackle these issues when we talk about source code and applications.
If these systems are so different, then how should they be approached in the context of the bill? First and foremost, without exception, open standards. Regardless of how they are built, these systems provide services. Their internal complexity matters not so much so long as they communicate with external systems using open standard format, without any prejudice to the nature of the client.
So again, we fall back to the FOSS-only reference implementations: The services must be accessible by the FOSS-only reference desktop. Any interaction with external servers must be tested against the FOSS-only reference server.
Finally, if any existing systems fail the FOSS-only reference test, the owning agencies must provide some form of gateway by which the systems can pass.