Re: Umax SuperMac

["Michael D. Crawford" <crawford@goingware.com>]

I never had much luck with the boot floppies, but it shouldn't be too hard to 
install the way I describe below.

What you want to do is install BootX and put the boot kernel in the Linux 
Kernels folder in the mac os system folder.

Put the ramdisk image anywhere on your hard drive, and when you launch bootx, 
direct it to the ramdisk image.

But before doing that, put the basedebs.tar on your hard drive too (all these 
need to go in an HFS partition - but it won't work for HFS+ partitions, as 
Linux doesn't understand HFS+ yet).

Note that the Umax SuperMac is an old world machine, like my 8500.  Look in the 
installation instructions and take special note of anything it says about old 
world Macs, and realize that some of what will work for a new world Mac won't 
work on your Umax.

For example, I found that the open firmware in my 8500 could be commanded to 
attempt a tftp boot, but it would never actually complete.  It would start to 
download a kernel and then hang.  But I understand tftp works OK for New World 
Macs.

While in the installer, repartition and format the drive that's not your 
startup disk.  (That means that the stuff you installed above has to be put on 
your startup disk).

If you really do want to eliminate all the Apple software, I think you can 
install yaboot on your Linux drive and then be able to boot without running the 
Mac OS at all - BootX runs as Mac OS software from a running Mac OS system, and 
then loads the Linux kernel.

  I think yaboot works for old world - however I've never tried it myself so 
check that out with someone else first, or maybe someone will reply about it here.

As long as you have a bootable Mac OS system, no matter how stripped down, you 
can boot Linux with BootX.  If you want to use BootX but have both drives using 
linux filesystems, repartition your first drive to have only a small HFS 
partition that's just big enough to hold a minimal system folder.  You will 
need several megabytes for each of your linux kernels because they are 
uncompressed.

But if yaboot works for you, you could probably then reformat both disks 
completely and be running totally free software.

Note that my 8500 won't boot if the hard drive that came with it isn't 
connected to the internal scsi connector.  I think there is something in the 
rom that keeps it from booting until it's been able to load the driver off that 
disk.  Putting any of my other Mac-formatted disks in its place doesn't work, 
that disk is somehow special.

So I would suggest that if you repartition your drives, that you keep the 
driver partition on all of them as it is.  Linux doesn't use the hard disk 
driver but it may be required to start up your mac.

I'm concerned that someday the hard drive that came with my 8500 will fail and 
then I'll be screwed.  I'd like to have a larger, faster drive there anyway, 
although narrow scsi-2 drives are hard to find these days, if anyone is even 
still making them.

The best guess I have of what to do about the boot problem is to copy the 
driver to the new drive I will someday get using sector-level reads and writes. 
 If anyone has a better idea I would love to hear.

I asked a couple friends I used to work with at Apple, who are both system 
software engineers who worked on the original OS for the 8500, and they had no 
idea it did that (that it won't boot without its original hard drive).  I was a 
system software engineer at Apple during the mid-90's, and the OS that shipped 
with the 8500 was my first project there, and I had no idea this happened until 
I tried removing my original drive a few months ago.

On a positive note, woody works just great on my 8500.  My woody 8500 is now my 
main desktop machine and IPMASQ server for my home/office LAN.

However, one more caveat - the kernel that comes with the woody installer hangs 
during boot on my 8500.  I had to use the potato install kernel to get my 8500 
installed, which caused problems with module versions that I had to fix up. 
After installing I was able to rebuild the kernel and that works fine.

The only real problem I ever have is that if I stress the machine really hard, 
so that the swap is thrashing really bad, it will eventually drop into the 
debugger.  That never happens during normal use though.

Best of Luck to You,

Michael D. Crawford
GoingWare Inc. - Expert Software Development and Consulting
http://www.goingware.com/
crawford@goingware.com

    Tilting at Windmills for a Better Tomorrow.