Mach and faulting in the file (Re: GNU Emacs, memory usage, releasing)

[Ted Lemon]

> The problem is that unless you copy the file on disk you can't back
> out of your edits at the last moment (:q! for vi people).  If you're
> going to copy the file you might as well copy it into vmem.

Actually, this isn't a problem with a proper virtual memory system.
If it's done right, you just implement a copy-on-write scheme with a
different version number for the modified file, as with TOPS-20.  BTW,
I believe (perhaps wrongly) that Emacs under TOPS-20 mapped its files
and did copy-on-write operations.   TOPS-20 has a studly memory
mapper.

			       _MelloN_