Large hard disk support in FreeBSD

[Chris Howells]

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Hi Robert,

On Tuesday 29 July 2003 01:10, Robert Watson wrote:

> Up until relatively recently, my main personal web service box was a
> Gateway 2000 P120 from '95 running FreeBSD 4.x, so I can speak to this
> with some confidence :-).  There are a few things you need to look at:

Many thanks for the answer, very informative. Has given me some confidence 
anyway :) Before I was hearing conflicting arguments some people claiming 
that the OS wouldn't be able to detect the disk if it was disabled in the 
BIOS, and others claiming that disabling it in the BIOS was the right thing 
to do.

> (1) BIOS revision.  Make sure you've flashed your BIOS forward as far as
>     possible -- some older Gateway 2000 BIOS's will hang if they see a
>     driver larger than they think is possible (I'm sure there's a better
>     technical definition, but the result is clear regardless :-).

Good point. Unfortunately Gateway's support seems to have gone completely 
AWOL, Gateway UK no longer offer any form of support and downloads, and the 
US Gateway site won't accept the machine's serial number so I'm not exactly 
sure what BIOS I have to download... well I downloaded one which seemed to be 
for an identical motherboard from the descriptions on the site but 
unfortunately I couldn't get it to flash... will have another mess around 
with that if I get problems.

> (2) Do you want to boot from the drive?  If I might suggest--don't even
>     try.  Boot from a drive known to work fine with the BIOS.  As you
>     suggest above, leave the drive unprobed (disabled) in the CMOS
>     configuration, which will help prevent the BIOS from tripping over it.
>     this will mean you can't use the drive in the loader before the kernel
>     is loaded, but since FreeBSD's device probing and management is pretty
>     much independent of the BIOS, it should work fine with FreeBSD.

OK, that sounds great. The machine has a 2 gig disk already which will remain 
the boot drive, the 80GB is going to be used for music/photos and stuff as 
I've managed to fill the 40GB in my laptop already :)

> (3) The ATA controller built into your motherboard may not support larger
>     disk addressing, although I think that shouldn't be a problem with
>     60GB.  If you try to use a drive larger than addressable using the ATA
>     controller, you may want to pick up a cheap PCI ATA controller (or get
>     the "kit" version of the drive that has a new controller).

Right, sounds like a good idea. Maybe a good idea anyway from a performance 
point of view since the board will support only UDMA 33 (is that the name for 
it?) whereas the new drive is meant to support UDMA 100. Hopefully the P150 
processor can keep up :)

> (4) Cabling and support for non-PIO.  I found that my older motherboard's
>     ATA controller had problems negotiating higher rate transfers from the
>     disk, so ended up disabling the DMA support for at least one of the
>     drives I added.  You will probably also want to make sure you're using
>     the newer cable that will come with any recent drive, since that will
>     help avoid quality and negotiation problems.  You might end up needing
>     to force PIO support anyway if you're getting occasional timeouts from
>     the drive.

Fine.

> That said, I ran just fine for about 8 years on my p120 -- I didn't want
> to take it out of service, but I needed more memory than the chipset could
> comfortably support.  Some of those systems can only cache the first 64MB
> of memory, so any additional memory is used uncached.  I ended up
> upgrading it to an E-Machine, go figure :-).  The old p120 is now back at
> home from colocation, and I'm sure I'll find a use for it at some point.

Nice. I'm running Squid, Samba, Pure FTPD, cups, bind, dhcpd, nfsd and ntpd 
and FreeBSD seems to be doing a very nice job :) 

- -- 
Cheers, Chris Howells -- chris at chrishowells.co.uk, howells at kde.org
Web: http://chrishowells.co.uk, PGP ID: 0x33795A2C
KDE/Qt/C++/PHP Developer: http://www.kde.org
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