Michael> This doesn't actually address the UNC question, but I'm
    Michael> pretty sure that conclusion when we last discussed it on
    Michael> the list was that the correct form (i.e. the one most
    Michael> likely to work) was file:////server/file/name - yes, four
    Michael> slashes.

Now that surprises me. I was expecting an answer like David Carlisle
gave:

file://server/file/name

    Michael> P.S. Does anyone think I ought to allow windows path names in places where
    Michael> the spec requires a URI? I'm disinclined to do it, but it does give people a
    Michael> problem moving to a product that enforces the rules strictly from one that
    Michael> doesn't.

You mean like in xsl:import href attribute? I think not.

My concern is allowing file names on a command line, and converting
them to URLs, which I think you already do with Saxon.

Grtz,
Geert