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Yes, they are special, but...

   Date: Wed, 14 Jun 89 23:07:14 EDT
   From: barmar@Think.COM

      But the point I was really making is not that timesharing improves
      performance, but that it improves *functionality*.  It's essentially
      impossible right now to use a LispM over a dialup; not that I would
      want to do so very often, or for very long at a time, but there are
      those occasions when it sure would be handy.  I know, I know, multiple
      address spaces and scheduling across page faults are not absolute
      requirements for that by any means.  But they do make it work better.

   I don't understand how process switching during page faults relates to
   using dialups AT ALL.  Assuming it improves performance, it will do so
   whether or not you're using a dialup.  Is multi-process performance
   only an issue when you're using a dialup?

I didn't explain this very well.  Process switching during page faults
is considered to be less important if there is only one user than if
there are multiple users, because with only one user there is usually
only one foreground process, so the user's perception of response time
is not improved if other things are being done while the foreground
process is paging.  With multiple users and multiple foreground
processes, it makes more of a difference.

   Even if you do this, what Genera needs much more to make dialup use
   reasonable is decent software to run on the dialup stream, e.g. a
   character-oriented text editor, and a way to interrupt a process.

Indeed.  These are additional points I should have added to my
somewhat cryptic comment about the unusability of Genera via dialup.

-- Scott