[Simh] write errors attempting to install 4.3BSD on vax; simh from git

[Brad Parker]

Hi,

I pulled the latest from the simh git hub and built vax730, vax750 and 
vax780.

I initially tried to install the UWisc 4.3+NFS from a tape image, using 
a recipe I found.
It fails when I try to "newfs ra0h ra81".  The error is "write error: 
759667"

It looks like the driver is trying to write past the end of the disk; 
but the rq code in simh is not seeing that.
It does not seem to be throwing any errors.

I'm not sure how to debug this;  I added some printfs to pdp_rq.c; There 
seems to be some debug disk logging inside simh but I can't find any 
docs about how to use it...

I also tried a stock 4.3BSD distribution and I see exactly the same 
behavior.

My memory is dim on where the partition info is, but I think in this 
case it's hard coded in the unix kernel.

I might go back and try some very old simh vax releases, since it seems 
like this use to work.  If anyone has any ideas or insight, I'm all ears.

-brad