Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!mips!twg.com!david From: david@twg.com (David S. Herron) Newsgroups: comp.sys.amiga.advocacy Subject: Re: Amiga OS *IS* state of the art Keywords: Amiga OS Message-ID: <8806@gollum.twg.com> Date: 30 Mar 91 03:39:09 GMT References: <1003@cbmger.UUCP> <7827@jhunix.HCF.JHU.EDU> Organization: The Wollongong Group, Palo Alto, CA Lines: 102 In article <7827@jhunix.HCF.JHU.EDU> barrett@jhunix.HCF.JHU.EDU (Dan Barrett) writes: >In article <1003@cbmger.UUCP> peterk@cbmger.UUCP (Peter Kittel GERMANY) writes: >>Just having scanned through the latest BYTE issue (March issue, >>they seem to use rowing boats to ship here to Europe), I gathered >>more confirmation for the fact that our Amiga OS really is state >>of the art in OSes: > > Now now... let's not get carried away. The Amiga OS is very, very >nice, that is true. I like it a lot. But no way is it "state of the art" >in the 1990's! > > For example, it doesn't have: > > - Virtual memory > - Memory protection > - Resource tracking > - Multi-user capabilities Yes, BUT -- these features are not NECESSARY. Further in order to have them you pay a performance penalty which, apparently, Commodore is unwilling to pay. Yes each would be very nice to have. To have virtual memory: Obviously most Amiga's don't have MMU's, a required piece of hardware there. Regardless I've never heard of an OS with virtual memory in which all processes shared the same address space. Currently AmigaDOS processes share the same address space & who knows what will break when that is changed. Yes I know about MEMF_PUBLIC & etc. I remember reading here, however, that a lot of programmers are lazy about setting that flag "right" ... Obviously a program which needs real time response for some reason cannot be swapped out. Adding a call to lock a process in memory would be necessary. Once the kernel is in a seperate address space than the other processes then system calls and interrupts become more expensive. That is .. context (CPU registers and such) need to be saved away. If pointers passed in system calls are not in public memory (that is, accessible by every process) then the kernel has to do funny tricks with the MMU to copy bytes in & out of user memory. etc. To add memory protection: Again this requires an MMU. Same comments apply as above. Both these would be nice though.. especially memory protection for all instead of just for developers. (Aside, there's a developer tool I've heard about which adds memory protection as an aid for finding things like wild/NULL pointers). Resource tracking: Well.. obviously the kernel needs to be keeping track of what it doles out & that means more code, eh? I really do NOT understand why this isn't there and don't see that doing it in a user program versus the kernel is going to be any faster. I remember one of the cbmvax.cbm.com crowd (Randall Jessup maybe?) claiming that he thought the right way for a process to exit is to commit suicide. **SIGH**! Opion-Time: One of the jobs of an OS (or as I see it) is to "beautify" the users/programmers environment. That is.. make it simpler than "raw hardware". Resource tracking is one of those boring jobs which programmers do not do well. Especially in C where there are no built in facilities to help out! (For more OS principles, I refer you to [Raphael Finkel] _An Operating Systems Vadae Maecum_ (Hope I spelled that right... been a few years since I looked at the book)). Multi-User capabilities: ***WHY***??? This is a single user machine, why do you want others to use it?!? 'sides, there's some PD-ware about which will do that.. UUCP for instance. Again from what I understand/hear-from-the-inside/etc it is a very conscious decision to not have those capabilities. >Even if it did, these ideas are *old*, and not "state of the art". Yes.. but still AmigaDOS is a very up-to-date OS having many features which are at if not close to state of the art. > If you want to see a "state of the art" operating system, take a >look at current research at places like University of Illinois (CHOICES) and >AT&T (various successors to UNIX; I forget the names). Jeez.. he left out Mach, Sprite and a few others. David -- <- David Herron, an MMDF & WIN/MHS guy, <- Formerly: David Herron -- NonResident E-Mail Hack <- <- "MS-DOS? Where we're going we don't need MS-DOS." --Back To The Future