In article <1992Aug17.151311.29507@ods.com> david@ods.com (David Engel) writes:
quoted text
> No, it wouldn't be shareable.  When a process writes to a shared page,
> it gets its very own copy of it which is no longer shared.

Yes, but you could add a system call that tells the kernel that the
next write access won't make the page(s) any dirtier, e.g.

    clean_write(caddr_t addr,int len)

Obviously, you'll run into nasty consistency problems if a different
version of the same shared library is installed and you better make
sure that this mechanism can't be used to subvert system security.
Might be nice stuff for a thesis ;-)

- Werner
-- 
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  / Werner Almesberger, ETH Zuerich, CH      almesber@nessie.cs.id.ethz.ch /
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