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From: Terry Lambert <terry@lambert.org>
Message-Id: <199604100104.SAA06406@phaeton.artisoft.com>
Subject: Re: Artisoft AE-3 Ethernet card: How to use large buffer?
To: Brett_Glass@ccgate.infoworld.com (Brett Glass)
Date: Tue, 9 Apr 1996 18:04:34 -0700 (MST)
Cc: terry@lambert.org, questions@FreeBSD.org
In-Reply-To: <9603098290.AA829087812@ccgate.infoworld.com> from "Brett Glass" at Apr 9, 96 02:04:51 pm
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> > You could always try it.  I don't think it will work, since it's
> > unlikely to have compatable gate array settings.
> 
> I'm not sure, but I believe that the internal buffer is not directly
> accessible on NE2000 clones. As I understand it, the RAM is accessible via
> programmed I/O after setting a pointer register. (This is one of the common
> criticisms of the architecture: PIO isn't quite as fast as shared memory.)
> 
> > You need to set mem_end to mem_start + 64k.  This should be done in
> > whichever probe routine is coming true.
> 
> Aren't the mem_end and mem_start parameters used for cards that have shared
> memory (rather than a PIO/counter scheme)?
> 
> > This assumes that, unlike some cards, there is not only an 8k window
> > to get at the memeory (in which case you want to leave it alone).
> 
> Again, I'm not certain, but I believe that access to the buffer does not
> take place via a memory window at all.

I was reading from the comments in the /sys/i386/isa/if_ed.c.  Search
for the string "mem_end".

I think you might be looking at the 3COM specific code?


					Terry Lambert
					terry@lambert.org
---
Any opinions in this posting are my own and not those of my present
or previous employers.