Thanks, but I want to stress that it is only partly my work.  I did the
original hacking to get the original XT-IDE onto the PCjr, but the
sidecar is way way far more advanced than that work.  Alan (not on the
list) did a great job with it.  It took a little debugging to get it
stable, but I've been using my machine happily since then.
If you've never seen a PCjr, don't despair - think of a near PC clone
that is almost impossible to upgrade because the expansion bus is
non-standard and you can have conflicts with the built-in goodies.
Having a PCjr that can boot from a hard drive directly using its BIOS is
a magical thing.  Like the XT-IDE, the intent is to use a modern IDE
drive that supports LBA access.  (Compact Flash with an adapter or Disk
On Module are equivalent.)  I've measured better than 300KB/sec reads
 from a Maxtor 20GB hard drive and 160KB/sec writes.
Now all we need is a native Ethernet adapter ...
Mike