I don't know if I linked to this paper before.
Web servers for embedded systems control
If you are interested, this paradigm is the primary reason I changed my notion of the way VOS should work between 2002 and 2005. After I began to understand it I realised just how powerful a single server can be and how easily the rest of a control network can be provided with nearly anything at hand.
If the server is designed to be one integrated unit with very few failure points (usually as a result of linking to external systems like an SQL database, for example) then all you have to do is to keep the server running and the whole system will stay running forever.
Over the years, I had scaled down my requirements again and again from dedicated military PCs to smaller PC/104 compatibles … but once I realised you can burn the server code onto nearly any thin client, I realised about 2011 that all the hardware for VOS you could ever need would be available as $1.00 surplus thin client devices, many of which have superior MTBF to military grade embedded boards.
My book on VOS (which is the only thing I will charge money for) will essentially assume everyone is building their control system on thin clients and I may even have several chapters on how to set up the most common devices like the ubiquitous Compaq 1100. If you spent more than $2.00 on VOS by the time you got it running, you probably spent too much money. Most of my monitoring sensors I now know how to connect to USB, CANBUS, serial and parallel ports would simply be parts stripped off cars, which there should be a big supply of after TSHTF.