Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!wuarchive!uunet!stanford.edu!msi.umn.edu!widener!brendan From: brendan@cs.widener.edu (Brendan Kehoe) Newsgroups: comp.unix.admin Subject: Re: Project Athena ( was Re: Non Destructive Version of rm) Message-ID: Date: 8 May 91 21:53:27 GMT References: <12049@mentor.cc.purdue.edu> <{#_**}@ads.com> <12074@mentor.cc.purdue.edu> Distribution: na Organization: Widener CS Dept Lines: 88 In <12074@mentor.cc.purdue.edu>, asg@sage.cc.purdue.edu writes: Henry Mensch wrote: >}this is not a distributed computing environment. replacing character >}terminals with x terminals (did you know that the x window system came >}from project athena and is an athena network service?) does not make a >}distributed computing environment. >} >Well, then i guess I do not have the correct definition of distributed >environment. The effect is basically the same though as I see it. I'd suggest you ftp pub/usenix/network_services.PS from athena-dist.mit.edu and give it a read. (If you don't have Postscript, you can do some creative vi or emacs replacments and have it in a roughly readable form.) You might have a different opinion of what a distributed system is and how Athena's net services model really cooks. (This is simply my impression -- I've never had any direct contact with them.) >}->We also have it here at GE where each person who has a workstation >}->can still log into anny workstation and be able to access his disk without >}->having to do mounting all over the place. If I want to get to a directory >}->/tmp on the system a294 I do cd //a294/tmp - no problem. >} >}and how do you think //a294/tmp gets there? magic? maybe the >}workstation *gasp* mounts a filesystem there for your use when you >}make such a request. maybe they're using an automounter? > >May be, but I am still not allowed to decide where to mount file system's >(that is preordained) and I do not have the root password. If you're on a client (and not a critical server), sure, it'd cause problems, but it would not be out of the question. >}->Oh, I like your setup even better now. Give all the users root! >} >}you obviously don't understand that (with single user hosts) any user >}can become root with little/no effort. project athena's architecture >}gets over this by making root (on a workstation) a commodity of >}limited value. our users don't get root privileges on servers (where >}data are kept and network services originate from). > >This is not neccessarily true. Please explain to me why it is >impossible to keep a single user system secure. in any event, >using Xterminals with some centralized system, it IS possible >to keep people from becoming root. Oh? And what's to stop someone from hacking into the centralized server and completely crippling *ALL* computing ability on your entire network? I can imagine some of the people on that Sequent that had Xterms hanging off of it would be mighty perturbed. While I can't say that the Athena method of distributing the server responsibilities among a bunch of machines is far better than others (I haven't the experience with both setups to make such a statement), I can say that simple logic shows how it works. (And a little reading about distributed systems in general helps, too.) >}bruce, you might do well to have a chat with the manager of UNIX >}systems at the computing center ... i know he has some clues about > >Here we go again. Did you learn that tactic from Jon? Just because >I disagree with you does not mean I am incapable of understanding. >I know full well the merits of Athena's setup. If you did, then you wouldn't be making such erratic hits at it. >1) If I am using Xwindows, and I do something CPU-intensive, I cannot > even get my pointer to move around at times, much less iconify >move or size windows. With Xterminals, since the graphics are handled >by the terminals processor, the function of your windowing environment >is (somewhat) independant of the load on the man system. 'Scuse me? How would running a CPU-intensive thing on an Athena client effect overall service? >2) Athena's setup does not take advantage of unused resources when > only a few people are logged in. My machine is just as slow when >I do a CPU intensive job whether all 1000 workstations are in >use, or if only 100 are in use. With the method that I advocate however, >My job can take advantage of those unused resources. Somehow I doubt that the system stays at precisely the same load when usage grows exponentially. -- Brendan Kehoe - Widener Sun Network Manager - brendan@cs.widener.edu Widener University in Chester, PA A Bloody Sun-Dec War Zone "Does this person look relaxed to you? Well, it's actually an experiment of Contour's new 565-E chair!"