Path: utzoo!attcan!uunet!cs.utexas.edu!news-server.csri.toronto.edu!helios.physics.utoronto.ca!ists!yunexus!davecb From: davecb@yunexus.YorkU.CA (David Collier-Brown) Newsgroups: comp.arch Subject: Hardware Support for OS operations (was Re: Porting OSes) Message-ID: <16461@yunexus.YorkU.CA> Date: 21 Oct 90 22:10:54 GMT References: <4462@trantor.harris-atd.com> <107038@convex.convex.com> <15007@hydra.gatech.EDU> <10734@pt.cs.cmu.edu> <10801@pt.cs.cmu.edu> Organization: York U. Computing Services Lines: 27 lindsay@gandalf.cs.cmu.edu (Donald Lindsay) writes: >Multics needed hardware support for rings. The ring idea was long >ago replaced by capabilities - a concept that relates well to the >recent interest in objects. Multics also need hardware support for its cache (!)... All too many things pushed the state of the art at that time. Some capability/object machines have >been built, and even sold. (Does anyone know how to characterize the >Biin machine?) HOWEVER, I have seen a number of success stories >where capabilities were supported entirely in software. It would be >interesting to discuss efficency, and portable OSes, in this more >modern context. Interestingly, the Honeywell machine that replaced Multics was a DPS-8 woith capability hardware, running GCOS. It worked **so very well** that individual developers got private copies of ``shared'' so that their errors wouldn't crash the OS. Not too sucessfull an implementation, methinks (:-)) --dave -- David Collier-Brown, | davecb@Nexus.YorkU.CA, ...!yunexus!davecb or 72 Abitibi Ave., | {toronto area...}lethe!dave or just Willowdale, Ontario, | postmaster@{nexus.}yorku.ca CANADA. 416-223-8968 | work phone (416) 736-5257 x 22075