Ages ago, I had to port an app from VAX Ada to Verdix.
It used a VMS-specific "Indexed_IO" package which had
to have a Verdix version created.  Due to the usual employee
innovation agreements, I can't offer it to the public, but something
similar might be a useful thing if someone wanted to re-invent it.

Just imagine some form of search tree and/or hash mechanism,
only replace the access types with Direct_IO.Count