For some months, I have been accumulating odd bits of DECish flotsam
and jetsam from Moo U surplus.  And, a friend has floated my way a
MicroVAX 3100.  My first attempt at a VAX 3500 running NetBSD was a
smoking failure.  I would like to give it another try, and see if
I can do a bit better.

The current MicroVAX 3100 has Ultrix 4.2 on one tiny RZ23 drive,
but the case has two more (which I may change out to RZ24's or RZ25's)
and it has an RRD42 cdrom and a 2-gig Tandberg 1/4 inch cartridge tape
(probably to be changed for a 525mb Tandberg).  The case is the double
high thing with the front door for accessing the bottom drive tray.
The terminal is a Wyse-85 into the serial port.

1.  What exactly is this machine, or how do I find that out from the
    boot roms?  It seems to be a MicroVAX 3100-20?

2.  Will it satisfactorily run NetBSD-VAX-1.4.1 (it seems that it
    should)?

3.  I have some additional DEC parts that might be useful for bringing
    things up (RZ55, TZ50, RZ24s, RZ25s).  What would be worthwhile to
    add externally or internally to the box?

4.  Using the existing Ultrix as the starting point, what would be the
    best way to approach installing NetBSD-VAX-1.4.1 on a drive, and
    then booting off that drive?

My thoughts were to add a pair of RZ24's, internally, removing the
second and third RZ23's, then use the remaining space on the first
RZ23 to unroll the boot image, and then dd it onto the second drive.
Then tape or ftp load the rest.

Since I have both the tandberg and the TZ50 tape drives, can a bootable
tape for booting/installing be made for either device from Ultrix, if
I use the second drive (RZ23 or RZ24) as workspace, and then the third
drive (RZ24 or RZ25) as the destination drive?

Can it be testbooted from the Ultrix?  I don't want to nuke the Ultrix,
until I am sure NetBSD is up and running correctly, AND I have a backup
recovery/reboot method in case it or I cause it to fail.

Any insights or suggestions are appreciated.

Thanks

Bob