sticky bit obsolete?

[William Roberts]

> is the sticky bit idea worthwhile?

We have 30 MG1 workstations on an Ethernet under NFS, each with
small (22 Meg) Winchesters.  Each machine has a Unix kernel
with basic bootstrapping stuff and about 12 Meg of swap space
(We need that much for one of our language packages) so most
executables will have to be held on the fileservers.

These machines are allocated to undergraduate teaching, so they
will be used for very different things at different times,
typically in edit-compile-run sequences.  To reduce traffic on
the Ethernet, we would like to "cache" executables on the local
machines and using that vast swap partition is very tempting;
is there any way to have a "fairly sticky" bit?

If we use the sticky bit as is, executables won't go away once
installed in the swap partition. What we need is some sort of
advisory sticky bit which keeps the executable on the swap
partition until someone else needs the space. A simple "least
recently used" freeing strategy would probably be adequate.

How hard would it be to do this, given that we don't need the
old-style sticky bit?  Is it a good idea or have I really
flipped this time?
-- 

William Roberts         ARPA: liam at cs.qmc.ac.uk  (gw: cs.ucl.edu)
Queen Mary College      UUCP: liam at qmc-cs.UUCP
LONDON, UK              Tel:  01-980 4811 ext 3900