Not so long ago Daniel R. Killoran,Ph.D. said:

> My system: IIvx 68M RAM
> tried 2 drives: Seagate 2 Gig
> Quantum 1 Gig Fireball
> Using ZTerm on a Mac IIx as serial console.
> 
> Got write errors on Seagate whenever tried to write past 1 Gig, so
> gave it up as boot drive.
> Partitioned Quantum: 0 Driver
> 1 Driver
> 2 Patches (very small)
> 3 NetBSD root & user (940 Meg)
> 4 NetBSD swap (128 Meg)
> 5 Extra (5 K)
> 
> Using Quantum, SBC kernel, installation followed manual until I tried
> (in the initial single-user boot) to edit rc.conf. Said "read only
> system"
> 
> Ok, rtfm. Looked up booting in messages. Discovered I should have
> used new MAKEDEV and ttys. Downloaded them & "cpin"ed them in place
> of originals. Also found out about "mount /"
> 
> Tried again. In single-user, tried "mount /". Said "sys not clean".
> Tried fsck. Told it to mark sys clean. It said reboot, so I did.
> Repeat of above. Said "sys not clean" AGAIN! fsck'ed again, but this
> time, instead of rebooting as instructed, tried "mount /" and it
> worked! Hot diggety!
> Then did cd /dev; sh MAKEDEV all
> Seemed to work - at least took a while & didn't complain.
> 
> Rebooted. This time NOT single user. Of course, it found rc.conf not
> configd, so dropped into single user. Tried ed rc.conf. Said "read
> only system" (sigh!) Tried "mount /" & various things, lost temper &
> went back to Mac. cpout'ed rc.conf to Mac; edited NO to YES; cpin'ed
> it back where it was; tried again.
> 
> Booted, NOT single user. Said "/dev/ttyE0: Device not configured" -
> But I thought I just DID that!

I don't think I followed precisely everything you said, but try the
following:

cd /
mount -rw /
cd /dev
./MAKEDEV all

Bob gave this to me when I had a (possibly) similar problem.

All the best.

Matthew