Path: utzoo!attcan!uunet!ncrlnk!ncrcae!hubcap!gatech!ncar!tank!oddjob!uwvax!umn-d-ub!nic.MR.NET!shamash!raspail!bga
From: bga@raspail.UUCP (Bruce Albrecht)
Newsgroups: comp.arch
Subject: Re: PEP: Page Execution Priviledge
Summary: CDC Cybers
Message-ID: <955@raspail.UUCP>
Date: 7 Oct 88 14:33:05 GMT
References: <2550@sultra.UUCP> <76700049@p.cs.uiuc.edu> <16017@ames.arc.nasa.gov>
Organization: Control Data Corporation, Arden Hills, MN
Lines: 18

In article <16017@ames.arc.nasa.gov>, lamaster@ames.arc.nasa.gov (Hugh LaMaster) writes:
] In article <76700049@p.cs.uiuc.edu> gillies@p.cs.uiuc.edu writes:
] 
] >do you prevent a user-call from transferring to some random
] >non-instruction on one of these protected pages?  In Multics, you
] >could only jump to the beginning of a protected segment, I believe
] >(ENTER).
] 
] May I assume that the mechanism permitted unrestricted branching WITHIN
] a particular code segment, and only restricted accesses OUTSIDE of the
] current segment via a protected CALL/ENTER?
] 
] So, how come everybody doesn't do it?

Well, the Control Data Cybers do it, so why don't you all go out and buy one.
We could certainly use the orders!

Bruce