These are the files from the first (more or less successful) attempt 
to port the x-kernel to the Paragon. It used scout non-preemptive
threads, which were ported to the i860.

Although the context switching and event handling worked, we decided
to abandon this solution due to the problem of interfacing with the
Mach out-of-kernel device interface, which was necessary to access
the HiPPI board. The problem was that the interface requires the use
of mach messages, and since Mach has no knowledge of scout threads,
once a thread halted waiting for a mach message, the process as a
whole would be suspended, what was clearly unacceptable.
