Subject: Re: installing/running 1.4D, continued
To: Frank van der Linden <>
From: Hauke Fath <hf@Melog.DE>
List: port-i386
Date: 10/11/1999 11:55:23
At 10:41 11.10.99 +0200, Frank van der Linden wrote:
>The rule of thumb on sysinst is: don't try to outsmart it. It will get
>the BIOS geometry right, except in some very rare cases. Don't mess
>with it the values, it'll lead to bad results. If the BIOS geometry
>values sysinst sees seem bad to you, first check the BIOS setup
>if they are reasonable in there. Only modify them in sysinst as
>a last resort, if they seem really screwed up. This should only
>be needed in about 1% of all cases.

Hum. So, the message is essentially: If you want to deviate from the 
sysinst default, you better roll your own, as sysinst will most likely make 
a mess of it...

I recall that this is what I learned the hard way about Apple's System 
7.5.x installers, where custom install would sometimes even lead to an 
unbootable system.

>The problem in the above (Jim's) case is a bug that was present in 1.4.1,
>where partitions could end up with a off by one error (off by one sector
>for the end of the partition, to be exact)..


1.4.1 is the current NetBSD release.

> > an AHA2940UW. Sysinst offered the "BIOS geometry" and the "geometry" that
> > the drive announced during boot. The former didn't get me anywhere, while
> > the latter worked; but I found that sysinst had messed up the MBR 
> partition
> > table by inserting the cylinder numbers from the "drive geometry". Luckily
> > I had scribbled down the original values (I had set up a small DOS
> > partition and set up the MBR partition tabl ewith pfdisk), so I was 
> able to
> > manually fix the cylinder values.
>See "don't mess with the values" above. Why didn't the BIOS geometry
>"get you anywhere"?

The "extended mapping" of the Adaptec controllers has something like 63 sec 
per track / 255 tracks (heads) per cyl. The ffs code wants very large 
blocksizes for this "disk geometry".

I dimly recall that there were other problems with this "geometry", and I 
recall I was too pissed of by the geometry crap to even take notes on it. I 
have some notes around on sysinst but they don't cover the "geometry" stuff.

It may even be that sysinst claimed the "BIOS geometry" to be wrong somehow 
and offered the "disk geometry" as shown during the disk probe as an 


Hauke Fath                              Saphir Software GmbH
                                         D-69115 Heidelberg
hf@SaphirSC.DE                          Ruf +49-6221-13866-35, Fax -21