Path: utzoo!utgpu!news-server.csri.toronto.edu!rutgers!usc!zaphod.mps.ohio-state.edu!uakari.primate.wisc.edu!crdgw1!barnett From: barnett@grymoire.crd.ge.com (Bruce Barnett) Newsgroups: comp.sys.mac.system Subject: Re: Protected-mode snake oil Message-ID: Date: 10 Aug 90 13:41:04 GMT References: <1204.26c2fb48@waikato.ac.nz> Sender: news@crdgw1.crd.ge.com Reply-To: barnett@crdgw1.ge.com Organization: GE Corp. R & D, Schenectady, NY Lines: 46 In-reply-to: ccc_ldo@waikato.ac.nz's message of 10 Aug 90 06:22:00 GMT In article <1204.26c2fb48@waikato.ac.nz> ccc_ldo@waikato.ac.nz (Lawrence D'Oliveiro, Waikato University) writes: > There was a discussion a while back about the virtues of protected operating > systems. A number of people seem to believe that PCs in general, and > Macintosh in particular, will become much more reliable once they start > to enforce a separation between user-level and kernel-level code. I feel that the bigger problem MacOS faces is the need to reboot the machine to install certain pieces of software. On some of our boxes that server hundreds of users, the last thing we want to do is to reboot the machine. The same should be true of MacOS, but I don't believe that will happen for years, if ever. > Frankly, I'm a little skeptical. As a regular user of both a Mac and > a VAX/VMS cluster, I'd have to say that the relative frequency of > crashes of the two systems, leaving aside the times I crash either > one while debugging my own software, is something in the region of > 10:1. That is, it's not as much as 100:1. If you crash the system while developing unpriviledged code, then that is an indication the system has serious bugs in it. It is not an indication that protected mode is meaningless. I have installed hundreds of software packages as an unprivileged user. I cannot remember one case where this software crashed the machine. It might crash my account, but the other users were unaffected. There have been cases of user mode programs crashing a system. This always indicates a serious problem in the system itself. > In short, the protection system on a typical multi-user machine > is there to protect users from one another; it affords *some* > protection to users against bugs in programs, but it would appear > that the commercial software for the big machines is just as > unreliable as the products for the little beasties we all know and love. This I disagree with, for the above reasons. Installing/running priviledged software is another issue. Yes it can crash a system. But then this is not the case of system mode vs. user mode. If system mode software brings the system down, the code is buggy. -- Bruce G. Barnett barnett@crd.ge.com uunet!crdgw1!barnett