Subject: Re: Is an MMU necessary?
To: None <>
From: None <>
Date: 07/26/2000 12:52:16
> People have indeed hacked Linux/BSD/etc to run on hardware with no MMU,
> but there are always significant sacrifices involved which they aren't
> very interested in talking about.
That's an understatement.
The first version of UNIX (besides the PDP-6 REALLY first
version) ran on a PDP-11/20, which doesn't have an MMU. I asked
Dennis Ritchie about this, thinking it must have been a single-user
system, under the circumstances. He said, no, it was indeed multi-user.
"All the terminals were in the same room. Whenever someone wanted
to test a program, he'd say, 'a.out?' And everyone else in the room
would go, 'w', 'q' [the command sequence to write out a file in 'ed',
and then quit]."
One bogus pointer and the OS and all the other programs
currently running are binary garbage.