/tmp emptied on boot on some systems but not others

["David Gaudine" <david@annette.concordia.ca>]

I have several Debian systems.  On two of them /tmp is emptied when I
reboot, but on the rest of the systems it is not.  I can't see the
difference between the systems.  They all have /etc/bootmisc.sh and the link
to it in /etc/rcS.d.  However, it appears that bootmisc.sh is not executed
at all on some systems.  It's supposed to be called by /etc/init.d/rcS.  As
near as I can tell, that file isn't being executed (I put a "touch
/root/somefilename" command in there, and the file is created only on the
systems that do empty /tmp).  I then tried this in inittab:
s2::sysinit:touch /root/inittab
si::sysinit:/etc/init.d/rcS
and that "touch" isn't executed either, but I'm not sure the line is valid.
Any ideas?
Note: it appears that I installed Debian in December 1995.  Perhaps after 7
years of running dselect it's a lot to ask for the system to act exactly
like my newest one.  (And perhaps after 7 years I should know how to work
the darned thing!)
David