schwartz@shire.cs.psu.edu (Scott Schwartz) (05/01/89)
In article <892@twwells.uucp>, bill@twwells (T. William Wells) writes: >In article <4523@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes: >: I think we need a good dose of Multics: Reading the time should be >: equivalent to accessing an object in virtual memory. In fact, the >: whole operating system system should behave like that, filesystem, >: system calls, and so on. > >Ack, NO! All we need is one rogue pointer and almost ANYTHING can >happen! > >That notion is attractive, but the separation produced by having >system calls means that a much smaller class of errors is likely to >do random things to your operating environment. No, no, no. Multics had an amazing protection scheme! System calls are implemented as special places in privliged rings that you are allowed to branch to. Touch anything else, and the system returns an access violation. The point is that the memory management system takes care of making sure users are playing by the rules, so that you don't need to do a context switch as such, possible via an expensive processor trap. Think of it this way: in Unix the filesystem has a more general protection scheme than does the vm system; you can indicate who (user,group,other) has access to what files, and for what operatons. Multics has general access control lists. So at the worst, ignoring all the good stuff that Multics could do for you, you reduce to Unix. By the way, are there any Multics sites still in operation out there? -- Scott Schwartz <schwartz@shire.cs.psu.edu>
ka@june.cs.washington.edu (Kenneth Almquist) (05/01/89)
schwartz@shire.cs.psu.edu (Scott Schwartz) asks:
> By the way, are there any Multics sites still in operation out there?
I thought there were, but it turns out that MULTICS.mit.edu is a VAX
running UNIX and HI-MULTICS.honeywell.com is a VMS system...
Kenneth Almquistlalonde@dalcsug.UUCP (Paul Lalonde) (05/01/89)
In article <8057@june.cs.washington.edu> ka@june.cs.washington.edu (Kenneth Almquist) writes: >schwartz@shire.cs.psu.edu (Scott Schwartz) asks: >> By the way, are there any Multics sites still in operation out there? > >I thought there were, but it turns out that MULTICS.mit.edu is a VAX >running UNIX and HI-MULTICS.honeywell.com is a VMS system... > Kenneth Almquist I believe the Canadian Armed Forces are still running one or two sites, although they are being phased out. Can anyone confirm this? Paul Lalonde Paul A. Lalonde UUCP: ...{uunet|watmath|utai}!dalcs!dalcsug!lalonde Phone: (902)423-4748 BITNET: 05LALOND@AC.DAL.CA "The only true law is that which leads to freedom" - Richard Bach, _Jonathan Livingston Seagull_
jdchrist@watcgl.waterloo.edu (Dan Christensen) (05/01/89)
In article <4525@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes: >By the way, are there any Multics sites still in operation out there? >-- >Scott Schwartz <schwartz@shire.cs.psu.edu> In 1986 there was one. I think it was at the University of Calgary (is that the right name?) but it may have been at the University of British Columbia. ---- Dan Christensen, Computer Graphics Lab, jdchrist@watcgl.uwaterloo.ca University of Waterloo, Waterloo, Ont. jdchrist@watcgl.waterloo.edu
Makey@LOGICON.ARPA (Jeff Makey) (05/02/89)
In article <4525@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes: >By the way, are there any Multics sites still in operation out there? There are 3 Multics sites listed in the latest host table from SRI-NIC.ARPA. I understand there are one or two dozen others that are not on the Internet. :: Jeff Makey Department of Tautological Pleonasms and Superfluous Redundancies Department Disclaimer: Logicon doesn't even know we're running news. Internet: Makey@LOGICON.ARPA UUCP: {nosc,ucsd}!logicon.arpa!Makey
woods@tmsoft.uucp (Greg Woods) (05/02/89)
In article <8057@june.cs.washington.edu> ka@june.cs.washington.edu (Kenneth Almquist) writes: >schwartz@shire.cs.psu.edu (Scott Schwartz) asks: >> By the way, are there any Multics sites still in operation out there? > >I thought there were, but it turns out that MULTICS.mit.edu is a VAX >running UNIX and HI-MULTICS.honeywell.com is a VMS system... There's at least one large MULTICS system running out there. It is at the University of Calgary. At least it's still on their Develnet, and appears to be running MR12 or something. I heard a rumor that they were busy helping Honeywell convert a lot of the Multics software to run under Unix (i.e. writing a PL/1 compiler for Unix :-). I don't have a valid account anymore, so that's all I can tell you. :-< -- Greg A. Woods. woods@{{tmsoft,utgpu,gate,ontmoh}.UUCP,utorgpu.BITNET,gpu.utcs.Toronto.EDU} +1-416-443-1734 [h], +1-416-595-5425 [w] Toronto, Ontario, Canada
jik@athena.mit.edu (Jonathan I. Kamens) (05/02/89)
In article <4525@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes: >By the way, are there any Multics sites still in operation out there? Well, dockmaster.arpa (of the NCSC, I believe) runs multics. Jonathan Kamens USnail: MIT Project Athena 410 Memorial Drive, No. 223F jik@Athena.MIT.EDU Cambridge, MA 02139-4318 Office: 617-253-4261 Home: 617-225-8218
cliff@cpsc.ucalgary.ca (Cliff Marcellus) (05/02/89)
In article <427@logicon.arpa>, Makey@LOGICON.ARPA (Jeff Makey) writes: > In article <4525@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes: > >By the way, are there any Multics sites still in operation out there? > Yup, the Uniuversity of Calgary still runs two very large Multics systems... Cliff Marcellus UUCP : {any backbone}!calgary!ssg-vax-a!cliff Institute for Space Research DOMAIN : cliff@ssg-vax-a.phys.UCalgary.CA Department of Physics SPAN : CANCAL::CLIFF The University of Calgary "If it's not fun, don't do it!"
barmar@think.COM (Barry Margolin) (05/03/89)
At the peak (about five years ago) there were around 70 Multics
systems worldwide. These days I think there are still at least 50.
Most of them are not in the US; the majority have been in France for a
long time, and the UK also has quite a few. In the US there are a few
at Ford and GM, a bunch in the DoD (including a couple at the
Pentagon), a few at universities (MIT shut theirs down at the
beginning of 1988), one at the National Computer Security Center
(Multics's security features permit them to give accounts to competing
vendors without worrying too much about spying), probably at least one
at the NSA, and a few others I can't think of right now.
Barry Margolin
Thinking Machines Corp.
barmar@think.com
{uunet,harvard}!think!barmarjeff@nucleus.UUCP (Jeff Marraccini) (05/03/89)
In article <4525@psuvax1.cs.psu.edu> schwartz@shire.cs.psu.edu (Scott Schwartz) writes: >By the way, are there any Multics sites still in operation out there? Oakland University in Rochester, Michigan is running a Multics MR12.2 system. I still log in occasionally :-) It's a nice system, but it tends to bog down. There are plans to eliminate it to recover floorspace for a newer system. Lately users have been migrating over to VMS and Unix systems, but the Multics still has the best PL/1 compiler on campus and some of the software on it still isn't available for any other machine. The new Multics releases even support Unix style pipes and file redirections from the command processor! Jeff -- Jeff Marraccini jeff@nucleus.UUCP ...!<internet>!sharkey!nucleus!jeff nucleus: Public access Unix, 313/623-6309, 1200/2400bps, no fee
dave@lethe.UUCP (Dave Collier-Brown) (05/03/89)
Actually the cost of a system-call equivalent in Multics was/is
comparable to system calls in Unix, as one usually had a ring crossing
required to do anything major (ie, something other than returning one's
process id). This meant calling a gate, having it double-check you, then
set up a new stack frame, then do the work.
The old call sequence was...
eaplp -*,ic
aos 2,ic
tra linq-*,ic*
arg 0
which means "do all sorts of stuff, then branch" (:-)).
Seriously, though, there were lots of good, subtle ideas in Multics. Some
deserve to be reinvented. Others deserve to be recorded as "classic, elegant
stupidity".
--dave
--
David Collier-Brown, | {toronto area...}lethe!dave
72 Abitibi Ave., | Joyce C-B:
Willowdale, Ontario, | He's so smart he's dumb.
CANADA. 223-8968 |igb@Fulcrum.BT.CO.UK (Ian G Batten) (05/03/89)
[People asking if there are Multics sites still in use]. Various UK academic sites acquired Multics machines towards the end; Birmingham U. loses its this year (for a 3090!), Avon's went last year, L'boro goes soon... ian -- Ian G Batten, BT Fulcrum - igb@fulcrum.bt.co.uk - ...!uunet!ukc!fulcrum!igb
friedl@vsi.COM (Stephen J. Friedl) (05/04/89)
> I believe the Canadian Armed Forces are still running one or two sites, > although they are being phased out. Can anyone confirm this? Canada has an Army? Steve :-) -- Stephen J. Friedl / V-Systems, Inc. / Santa Ana, CA / +1 714 545 6442 3B2-kind-of-guy / friedl@vsi.com / {attmail, uunet, etc}!vsi!friedl Breaking a collerbone is a great way to cut down typing speed :-(
ragnar@dvlmarv.UUCP (Ragnar Paulson) (05/06/89)
In article <1113@vsi.COM> friedl@vsi.COM (Stephen J. Friedl) writes: >> I believe the Canadian Armed Forces are still running one or two sites, >> although they are being phased out. Can anyone confirm this? > >Canada has an Army? > I believe they are still running one or two sites, although they are being phased out. :-) Ragnar -- Ragnar Paulson uunet!mnetor!lsuc!dvlmarv!tsgfred!ragnar The Software Group Limited 4701 Steeles Avenue West, Suite 201 Weston, Ontario, M9l 1X2
dave@lethe.UUCP (Dave Collier-Brown) (05/06/89)
In article <1113@vsi.COM> friedl@vsi.COM (Stephen J. Friedl) writes: >> I believe the Canadian Armed Forces are still running one or two sites, >> although they are being phased out. Can anyone confirm this? > >Canada has an Army? Well, I wouldn't call it an **army**, but we do have a brigade. Seriously, though, we have at least one Multics machine still in use, which was doing some publishing work with (possibly multi-level) classified documents. Since it's classified, I don't get to know for sure. --dave c-b -- David Collier-Brown, | {toronto area...}lethe!dave 72 Abitibi Ave., | Joyce C-B: Willowdale, Ontario, | He's so smart he's dumb. CANADA. 223-8968 |