> No big deal. I have been trying to figure out a simple way to get a miniroot
> booted and wanted the bootblocks to grab /boot out of the b partition. I
> just added an offset to the block number to romstrategy() to do the same
> thing. Since I noticed some mention of TK50 in comments, have you been doing
> anything about bootstrapping a root fs onto disk from tk50?

Yes. At home I've a preliminary version of bootblocks and /boot which
boots from TK50, loads /boot, then /boot loads and executes the kernel
from tape. The idea behind is to dd a complete filesystem (e.g. ra0a)
onto tape, mount the tape as root-device and use to tools on the tape
to disklabel/newfs/populate the disk. For now it's possible to mount 
disks as root-device, but it's still impossible to mount tape (tms0) 
as root-device. I tried to find out why the kernel refuses to mount
tms0 as root-device but didn't succeed yet ...

I had (and still have) some problems with corrupted in-memory-copies
in the bootblocks, but now bootblocks/boot from TK50 work as well
(whatever that means :-) as from disk/floppy.

> (My current thought is just a little program that copies bootblocks and
>  a miniroot image (dd) onto disk from memory. ie. this program + bootblocks +
>  the miniroot would be concatenated together and then loaded into memory by
>  booting it off tk50.)

That's almost the way I disklabeled ra0a the first time on a machine
without OS. (I raw-wrote to contents of a bootable floppy onto the disk,
the floppy had patched bootblocks and an 1.2 MB filesystem on it.)
Then it was possible to boot from disk. But since only the first 1.2MB
of the filesystem were "real", I saw no way to produce a working 
boot/root-partition (you can't disklabel/newfs the device you've mounted
as root-device and remount/populate later, can you ???)

What I did next (but this does only work if you have two disks) 
	- boot from ra0, mount ra0 as root-device
	- (eventually newfs/mount/populate ra0g as /usr)
	- use tools on ra0g/usr or via nfs to perform next steps
	- disklabel the second disk
	- newfs ra1a and ra1g ==> valid filesystems on ra1
	- populate ra1 via nfs/ftp
	- reboot from ra1
	- disklabel/newfs ra0
	- populate ra0
	- it's done

But since for this procedure a second disk is needed I don't think that
this could be a general solution.

I don't claim to be an expert on this. You could make me real happy
if you tell me that I've overlooked/misunderstood something important.

> Unless I here that you have something else going, I'll do this and let you
> know how it goes.

Things would be easier if it would be possible to mount floppies or
tapes as root-device. But none of them works so far ...

Ciao,
	bertram