Date: Mon, 13 Jan 1997 19:34:59 -0700 (MST) From: Softweyr LLC <softweyr@xmission.com> To: grog@lemis.de Cc: questions@freebsd.org Subject: Re: the UNIX hole Message-ID: <199701140235.TAA03540@xmission.xmission.com> In-Reply-To: <199701130102.TAA00396@papillon.lemis.de> from "Greg Lehey" at Jan 12, 97 07:02:50 pm
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Mike Branch writes:
% could anybody give an explanation about the UNIX "hole"?
% Is the hole filled in current versions of UNIX? Is it
% still advisable to configure devices in contiguous memory
% locations when building a kernel?
Greg Lemis replied:
> (You can tell how far behind I am with my mail :-()
>
> I didn't see a reply to this one, and since I've never heard of the
> "UNIX hole", I thought I'd ask you what you mean.
I skipped over this when I first read it because it sounded like the
original author was from outer space. Now that I've seen it again, and
my brain has had a few days to rebuild the associative links, I
remember some bizarre problems running SVR3 apps on early i386 SVR4
systems, something to do with a giant hole placed between the text and
data segments when the program loaded.
If this is what you're talking about, Mike, it has never existed in BSD
UNIX, and still doesn't. ;^) And no, you can configure devices pretty
much wherever you want in memory, though on the PC architecture* most
devices use only I/O addresses and not memory addresses.
* Sorry, the phrase "PC architecture" just sent my brain spinning, I'm
trying to recover. The idea that someone actually *designed* this mess
boggles...
--
"Where am I, and what am I doing in this handbasket?"
Wes Peters Softweyr LLC
http://www.xmission.com/~softweyr softweyr@xmission.com
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