Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!swrinde!zaphod.mps.ohio-state.edu!rpi!crdgw1!crdos1!davidsen
From: davidsen@crdos1.crd.ge.COM (Wm E Davidsen Jr)
Newsgroups: comp.arch
Subject: Re: Segmented Architectures ( formerly Re: 48-bit computers)
Message-ID: <3304@crdos1.crd.ge.COM>
Date: 2 Apr 91 14:28:23 GMT
References: <1991Mar27.193512.12417@cello.hpl.hp.com> <1044@shum.huji.ac.il>
Reply-To: davidsen@crdos1.crd.ge.com (bill davidsen)
Organization: GE Corp R&D Center, Schenectady NY
Lines: 20

In article <1044@shum.huji.ac.il> amos@shum.huji.ac.il writes:

| One case you forgot is that of many small segments, which together
| amount to more than one segment size.  You could end up thrashing
| between different segments even if no single object is big enough
| to overflow a segment; all the arguments about big objects do not
| hold in this case.

  Huh? He said that a segment is as large as max addressable memory, and
you say if the sum of all segments is larger than physical memory it
will thrash. I see thrashing all the time without benefit of segment,
whenever the virtual address space used is larger than the physical
memory. What do segments cost?

  Not a flame, I just miss the point. If you don't have enough
addressable physical memory you thrash, in my experience.
-- 
bill davidsen	(davidsen@crdos1.crd.GE.COM -or- uunet!crdgw1!crdos1!davidsen)
        "Most of the VAX instructions are in microcode,
         but halt and no-op are in hardware for efficiency"