At 12:00 PM -0800 12/4/01, Bill Studenmund wrote:
>On Mon, 3 Dec 2001, Henry B. Hotz wrote:
>
>>  >  > I have been able to boot an MS-DOS floppy created by copying
>>  >>  ofwboot.xcf and the install kernel to the floppy on a 7500 and a
>>  >>  PowerBook (PDQ), but only by setting load-base to 500000 instead of
>>  >>  the recommended 600000 in both cases.  I find this preferable to
>>  >>  hunting up a way to create the official boot floppy under MacOS.
>>  >
>>  >Did it matter that the address was 500000, or was it just that it was not
>>  >600000? I've found with netbooting, that 640000 works. Basically ANY
>>  >address other than the load address works. :-)
>>  >
>>  >I think what happens is that the loader uses load-base as a scratch area,
>>  >and then copies the loaded file (ofwboot.xcf) to where it's supposed to
>>  >be.
>>
>>  I thought the load address was 6C0000.  I forget the command to check
>>  that in 1.5.2 release.  I didn't try 4000.  I just tried a random
>>  other number to see if it made a difference.
>
>ofwboot USED to load at 6c0000, but we ran into problems, so we moved it
>to 600000.
>
>>  Note that 600000 works fine with the boot floppy image.  I thought
>>  the netbsd install kernel and the ofwboot.xcf were supposed to be the
>>  same with the same load addresses.
>
>No, the kernel and ofwboot have different load addresses. owboot is at
>600000, and the kernel starts at 100000.

I didn't say that right.  I meant that the ofwboot.xcf and 
netbsd.ram.gz files were the same as the files hidden on the floppy 
image.  Therefore the only difference between the boot floppy and my 
MS-DOS boot floppy should be the filesystem type and the form of the 
OF boot command.

That's *still* not true though since ofwboot.xcf is an XCOFF load 
module while the boot floppy contains a simple, literal, executable 
image based on that module, doesn't it?

>Right about the floppy image; my findings were that for floppy loading,
>load-base had to match where the file should get loaded, and for
>netbooting it should *NOT* match.

Ugh!  I *hate* it when you have contradictory requirements.  I don't 
think I tried 500000 with the floppy image.

>  > I agree that it isn't really hard, given a web browser and an
>>  internet connection to go get suntar and write the boot floppy image.
>>  But when I'm setting up a green machine for NetBSD I'd like the
>>  minimum required tools to get started.  If the floppy image were
>>  packaged so it would work with DiskCopy directly that would be nice
>>  since that tool is usually on the Mac OS CD-ROMs.  (At best, and at
>>  worst it's no harder to get than SunTar.)
>
>Unfortunatly I'm not sure if we know how to make diskcopy images. :-(

There was a thread on the subject a few months ago.  The correct 
answer depended on both the OS version and the DiskCopy version. 
Sure would be nice if the boot floppy was a macbinary of a DiskCopy 
image though.  Or else an image with some known file type/creator 
that would make it acceptable to DiskCopy.

>I thought the newer versions could handle a raw file but I'm not sure.

I think it was OS >9 and some specific DiskCopy versions or OS <= 8.1 
(or <= 8.6) and some different DiskCopy versions.  I do not remember 
the specifics.  I do know that when I tried pointing whatever version 
I had at the image on the iso CD while running 9.1 it didn't work.
-- 
The opinions expressed in this message are mine,
not those of Caltech, JPL, NASA, or the US Government.
Henry.B.Hotz@jpl.nasa.gov, or hbhotz@oxy.edu