Path: utzoo!utgpu!water!watmath!atbowler From: atbowler@watmath.waterloo.edu (Alan T. Bowler [SDG]) Newsgroups: comp.lang.c Subject: Re: data validation (was re self-modifying code) Message-ID: <20350@watmath.waterloo.edu> Date: 14 Aug 88 17:23:00 GMT References: <61251@sun.uucp> <3084@geac.UUCP> <61866@sun.uucp> Reply-To: atbowler@watmath.waterloo.edu (Alan T. Bowler [SDG]) Organization: U. of Waterloo, Ontario Lines: 18 In article <61866@sun.uucp> guy@gorodish.Sun.COM (Guy Harris) writes: >> This is for a machine which happily passes descriptors of arrays >> around, and manages to bounds-check array references in parallell >> with the fetch. > >Umm, err, what machine is that? Doesn't sound like the GE 645 or the >successors that I knew of; as I remember it, the 645 and the HIS 6180 were >fairly "conventional" machines in most regards, with no automatic >bounds-checking for array references. (Maybe some of the weirdball "indirect >then tag" addressing modes could do this, but I don't think the PL/I compiler >made much use of most of them.) Guy is right. I think Dave is getting confused with the segmentation and capability hardware of the other large Honeywell machines. (L66, DPS-8, DPS-88, DPS-90, DPS-8000 etc). The Multics boxes were really just modified DPS-8's, but they did not have the same capability features. The protection mechanisms were done by the same designer, who basically said "what did I do wrong on Multics?".