Path: utzoo!utgpu!utstat!jarvis.csri.toronto.edu!mailrus!iuvax!rutgers!bellcore!texbell!uhnix1!sugar!peter From: peter@sugar.hackercorp.com (Peter da Silva) Newsgroups: comp.sys.amiga Subject: Re: UNIX vs. Amiga speeds Message-ID: <3663@sugar.hackercorp.com> Date: 22 Mar 89 12:20:50 GMT References: <6352@cbmvax.UUCP> <6359@cbmvax.UUCP> Organization: Sugar Land Unix - Houston Lines: 32 In article <6359@cbmvax.UUCP>, ditto@cbmvax.UUCP (Michael "Ford" Ditto) writes: > Hmm? Deven and Dave both seem to be saying that Unix requires paging, > which isn't true. Back to the old confusion between virtual memory and mapped memory. UNIX absolutely requires mapped memory. > I'm not > convinced that either Unix or AmigaOS is inherently "faster" overall. You can add those things (big caches, for example) to AmigaOS. You would have to completely rewrite the UNIX kernel to get the advantages of AmigaOS in UNIX (which I think would be a really good idea, by the way... AmigaOS would make a great real-time kernel for UNIX). > Then again, it might not, because there are situations where AmigaDos > uses more memory than Unix (such as stack space, for example -- how > many people always use a 10K or 20K stack size because of that > occational program that needs it). UNIX does not require, nor does it always support, dynamically allocated stacks. For example, early 68000 UNIX didn't support dynamically allocated stack because even without an MMU the 68000 couldn't recover from the page fault (yes, page fault) when the user tried to write into non-allocated stack space. Some systems tried to use stack probes to get around this problem, but they were unreliable. Even today, many 80286 UNIXes don't support dynamic stacks. We have '286 programs that preallocate up to a full segment for the stack. -- Peter "Have you hugged your wolf today" da Silva `-_-' ...texbell!sugar!peter, or peter@sugar.hackercorp.com 'U`