5400 binary and 3100 binary, are they compatible both ways?

[Jim Gettys]

As far as I know, (and we've run all sorts of Ultrix 3.1 and 4.0 variants
on 3100's, 2100's, 5800's and 5000's here at CRL),
you should have no trouble with any application except those which look
at /dev/kmem and /dev, which have differences (as usual) between releases.
This is the typical caveat for Unix systems in general.
As usual, as well, no guarantees on downward compatibility between releases.
We share a single /usr/local on all of our machines here with no problems,
with both 3.1 and 4.0 represented.

Someday (read OSF/1) /dev/kmem should be less of a problem when we have a
tables system call...  And the device numbers should not have to change again,
either.
			- Jim