kap1@phyllis.math.binghamton.edu (Dietrich Kappe) (09/15/90)
First the gripe: I called up PH today to find out postage and handling costs. In the process, I found out that I won't get a $60 discount on the Mac version, since the earlier version I bought was for the PC. (Of course there was no Mac version back then, but thats beside the point.) Is this official policy on PH's part, or did I just run into a salesperson who erred on the side of caution? Now my question: Does MacMinix switch user processes into user (68000) mode, or does it allow user programs to execute supervisor mode instructions. If the above method is not used, then does the included cc check for illegal operations (like overstepping memory bounds)? The thrust of my question is whether MacMINIX can be used as a secure multiuser system. --Dietrich-- ______________________________________________________________________________ | | | | kap1@phyllis.math.binghamton.edu | "Suspicion is the badge of | | | base-born minds, | |_______________________________________| And calculation never | | | understands." | | "My opinions are entirely my own, | -Virginia Moore | | for who else would want them?" | Tragic Conclusions | | | | ______________________________________________________________________________
archetyp@uxh.cso.uiuc.edu (Joseph R Pickert) (09/17/90)
kap1@phyllis.math.binghamton.edu (Dietrich Kappe) writes: >First the gripe: I called up PH today to find out postage and handling costs. >In the process, I found out that I won't get a $60 discount on the >Mac version, since the earlier version I bought was for the PC. (Of >course there was no Mac version back then, but thats beside the point.) Is >this official policy on PH's part, or did I just run into a salesperson >who erred on the side of caution? I don't know, but my guess is that this is the official policy. I don't think it would be any different if you went to Microsoft, say, and tried to do the same sort of thing. >Now my question: Does MacMinix switch user processes into user (68000) mode, >or does it allow user programs to execute supervisor mode instructions. If >the above method is not used, then does the included cc check for >illegal operations (like overstepping memory bounds)? MacMINIX user processes run in supervisor mode. This is required to make it run under the mac os, where all programs also run in supervisor mode. But assuming it ran in user mode, lack of memory management hardware on the low end macs makes any discussion of "security" virtually worthless. >The thrust of my question is whether MacMINIX can be used as a secure >multiuser system. No, see above. A better question might be this: can the REAL AT&T UNIX be used as a secure multiuser system? Joe Pickert