After considerable messing around, I have managed to get NetBSD installed
on my 3/50. I got the patched installation, built a boot tape and
lo and behold, I was apparently able to install the miniroot. Quite 
quickly too! Unfortunately, it didn't work. Booting the miniroot
appeared to load the kernel OK but it would just hang at some point short
of getting a shell prompt.

I used another machine to get the miniroot onto the swap partition. Then
I could boot the miniroot OK. However, when running the install
script it would get so far  and then give me a whole lot of garbage
messages similar to what I might expect if the shell were trying
to interprete garbage. You can ^C. But any new program you run
executes similarly. (eg update). Running pretty much anything
works fine straight after the reboot.

Setting the si_options to 0 works, and has enabled me  to install
the complete system including X11, but it has taken all weekend ;-(.

This is with a emulux md21 adaptor and a Toshiba MK 156F disk, but it
behaves the same with a Fujitsu disk. I wonder if there is anything
funny about the DMA hardware on this machine (different revisions or
something).

Anyway, it is a pity that the DMA doesn't work, but at least I don't get
the expected 10 bytes got six message any more!

I have had miscellaneous panics. Xsun would panic the kernel before
I created the bwtwo device. It is understandable that it doesn't work
but causing a panic seems a bit over the top! Unfortunately, none
of the other panics semm to have an obvious cause.

Ian