Subject: Re: aha0: DMA beyond end of ISA
To: Michael L. VanLoon -- <>
From: Sean Berry (most of the time) <>
List: current-users
Date: 11/09/1996 12:47:19
>If you indeed have 16MB of RAM, your BIOS might be pushing some little
>unusued block just over the 16MB limit.  You can either convince your
>BIOS not to do this (depends on your BIOS), or hard-code the amount of

He clearly stated that he had 32M of core.

>Or, you can find an unsupported patch that's been floating around,
>that gives you a bounce-buffer band-aid, to make the thing work.

Thanks very much to the author of it, it's allowed me to continue using
NetBSD where many of my friends on this campus have had to move to OpenBSD.

>The best fix is to just get a better SCSI controller (and a better
>motherboard if yours doesn't do PCI, EISA, or VLB).  This will not
>only avoid the problem without resorting to hackish bounce-buffers,
>but will also be _substantially_ faster.

It seems everyone else gets to be an asshole on this list, so I might as
well.  The best fix does not involve dollars.  Many people running BSD (I
daresay -most-) running NetBSD are either running it on various PCs which
they may or may not have the budget to upgrade, or on esoteric workstation
hardware they'd be lucky to -find- upgrade hardware for.

The bounce buffer solution works, seems to work well.  In my particular
case, if I can't get the aha1740 that came with the nice EISA machine we
just acquired to run under BSD, I have two choices.  I can either run Linux
on it, which it seems to very happily do, or I can put another SCSI card in
it.  The EISA box does not have VLB, nor does it have PCI.  Thus, I now need
to replace the entire machine if I cannot make an ISA SCSI card work in it,
or I have to tear memory out of it until it has only 16M.

Clearly removing memory is not, as Michael Graff would say, 'the correct
solution.'  Replacing the motherboard and (by the nature of the box, the box
itself) with another defeats the entire purpose of having NetBSD, as a
better operating system.

On the LKM topic, someone noted that often those running BSD are doing so to
get away from a far worse operating system.  I -can- run something else on
this box, but I really -want- to run BSD.  Since I have to use an ISA scsi
card, I'll grab the AHA1542 out of the NT box.  Whoops, caught again.

See where I'm going?  I really appreciate the effort being put in by people
with the skills to make this go, and especially Jason Thorpe, who seems to
put in fantastic hours for problems that don't even affect him.

It's the attitudes of those who tell the new NetBSD people that their
hardware is the reason they can't run NetBSD that drive people away.  I can
handily name you one person who came to NetBSD before I did, and one who
came after, who both run OpenBSD, simply because their 1542 will run in
their machines.  

Don't let Michael VanLoon or whoever else would tell everyone that the
solution is in the hardware drive people away from NetBSD before they've
even come.

>This is a well-documented problem.  Please see the appropriate FAQs,
>and/or consult the mailing list archives on

I appreciate the well documented and otherwise reasonably posted reply.
Sean Berry is a computer scientist trapped in an engineer's mind.
I imagine someone is likely to misinterpret my opinions as those of my
various employers.  This is not the case.