The session data, that would have been fantastic to have in a relational, queryable, reliable and trustable format was stored as a single giant string of PHP pickled data structure in a session file associated with the users cookie id.

XML-DOM page templates stored in a database, line by line.

So rendering a page started with:

select * from pages

where page_id = ‘index’

order by line_number asc;

Each line of XML from each record was appended into a single string. This string was then XSLT transformed to HTML, for every page load.

I guess I don’t see how tying the radio to a PoE microcontroller improves your resilience. Just changes the critical system.