Reporting success for posterity, I've managed to get NetBSD
sun3x up booting from a Jaz disk.  My stuff:
	
	Sun3/80, motherboard rev 10r50, bootrom rev 3.0 16MB RAM.
	1GB jaz drive (Mac formatted cartridge, not like it matters)
	Another 3/80 running SunOS 4.1.1 U1 as the boot host
	A 3/50 running NetBSD 1.2 off an Sun (emulex/micropolis)
	135 MB beater.
	
	I got Jeremy's kernel booting off the net before, however my
attempts to get it to boot off disk hadn't worked so good, probably
due to the disks I was using. I have a couple of old Sun emulex drives
(the kind with a Micropolis 1355 135MB ESDI drive and an Emulex SCSI
board that makes them look like SCSI to the machine.) I've used these
as my NetBSD 1.2 sun3 drives for a variety of sun3's for quite a
while. Unfortunately for whatever reason, the 3/80 seemed absolutely
determined not to see the Emulex disk drive. Strange since the 3/50
and 3/60 like them just fine, mind you these aren't exactly normal.

	Being a glutton for punishment and not having another drive 
handy I snagged a Jaz drive for a while (If anything's not normal
that is :) My method:

	1) Plug JAZ drive into my Sun3/80 running SunOS 4.1.1, and 
label it. the format.dat entry for 1GB Jaz as follows:

disk_type = "Jaz 1GB" \
        : ctlr = MD21 : fmt_time = 4 \
        : ncyl = 1018 : acyl = 2 : pcyl = 1020 : nhead = 64 : nsect = 32 \
        : rpm = 3600 : bpt = 16384

partition = "Jaz 1GB" \
         : disk = "Jaz 1GB" : ctlr = MD21 \
         : c =  0, 2084864

	I then ran format->partition, gave it 32MB root (a) and swap
	(b), with the rest in /usr (g). 

	2) Plug Jaz drive into a NetBSD 1.2 Sun3/50, boot 3/50.
	
	newfs /dev/rsd2a; newfs /dev/rsd2g
	mount /dev/sd2g /mnt
	dump 0f - /dev/rsd0g | (cd /mnt; restore rf -)
	sync
	umount /mnt
	mount /dev/sd2a /mnt
	dump 0f - /dev/rsd0a | (cd /mnt; restore rf -)
	sync
	shutdown -fh now

	3) Plug Jaz into 3/80 id 0, Boot netbsd sun3x from net, -a, tell
	it that root and swap are on the jaz disk.

	b le() -a
	...
	boot: netbsd.sun3x
	...
	...
	root filesystem: sd0a
	swap: sd0b
	root filesystem type: ffs
	......
	
	4) put kernel in place and install sun3x boot block ( I had
	put in /usr/mdec/sun3x)
	
	cp /netbsd.sun3x /netbsd
	cd /usr/mdec/sun3x
	cp bootxx /boot.sun3x
	cp ufsboot /ufsboot
	sync
	../installboot /ufsboot /boot.sun3x /dev/rsd0a
	sync 
	shutdown -fh now

	5) Boot from Jaz
	b sd(0,0,0)

	All seems as expected. (caveat known stuff ps and everything kvmish)
	Am in the process of building my own kernel and updating utilities.

	-Bob

--
Bob Beck					 Obtuse Systems Corporation
beck@obtuse.com					 http://www.obtuse.com/	
True Evil hides its real intentions in its street address. Search and you
shall find it, and the truth shall set you free.