>NetBSD/vax on this "Vaxstation 3100 M38".  However, the support pages show
>conflicting information about whether or not this machine is supported -
>anyone know for sure?

Yes, this machine will run NetBSD/vax very nicely.  The full v1.3.2 
distribution is available on the NetBSD web site.  For the kernel, you may 
want to use the latest (development) kernel available at: 
ftp://multivac.ludd.luth.se/

>In any case, this machine came with a DEC RZ23 hard drive, which should be
>100MB.  Is it likely that this machine fully booted off this hard drive?
>Or was it booted off a network?

I have one of these booting from a Linux box just fine.  I believe the
distribution, if trimmed properly, may fit on an RZ23 though it'll be
tight.

For netbooting, see the most excellent VAX-netboot-HOWTO available at
Planet VAX: http://world.std.com/~bdc/projects/vaxen/index.html

>Speaking of hard drives, this machine came with a SCSI interface.  There
>seems to be some kind of SCSI card on the "top rack" in the back of the
>computer, with SCSI cables going to a drive that exists, and to an empty
>space, which I figured someone removed the drive from.  Additionally, I

This system has two SCSI busses - bus 'A' is the one internal to the
system and bus 'B' is the one that goes to the external connector.  There
has been some problems with the NetBSD/VAX using the SCSI busses on the
M38.  I'm not sure what the latest status on this is, but a search through
the NetBSD/VAX distribution list archive should come up with the answer.

>found what looked to be a SCSI2 interface on this card pointing out of the
>back of the computer (it also had a terminating plug).  Is this really a
>SCSI2 interface? Maybe I'm underestimating vax technology here.

I don't believe it's actually a SCSI-2 interface, just SCSI-1, though a more 
experienced VAX geek could answer that more definitively (I'm still a bit
new to this myself).  There is a cable (DEC BC09J) that mates with the 
68-pin connector on the VS3100 and has a normal 50-pin SCSI-1 connector on 
the other end.

>Oh yeah...where is the RAM in this thing?! I opened it up, and found no
>chips that resemble RAM, nor any slots to indicate the lack thereof.  If
>the RAM is soldered on the board, how much is there?

The RAM is on a large card near the front of the unit - the card connects
to the system board via two connectors (50-pins each, I believe), and four
plastic post locks.  The card itself is upside-down.   If the system has
a total of 16, 24, or 32 MB, then the memory module will have a second
memory module attached to it.  If the system has 8, 12, or 20 MB of memory
it will have only one memory module.  

There is also 4 MB on the main system board.

>I plugged everything to the back of the machine, including a Vax monitor
>(with it's coax-to-15-pin connector), a mouse that looks like a hockey
>puck, a keyboard, a AUI<->10Bt tranceiver, and power cords, and started the
>machine up.  I'm not exactly sure what the bootup was supposed to look
>like, but I heard intermittent beeps, in sync with the blinking light on
>the floppy disk drive and the lights on the keyboard.  Anyone know what I
>should do next? Looks like some kind of warning message or something. :-\

You should get a countdown (in hex) indicate that the self-test is running, 
followed by a ">>>" prompt, with the possibility of some error or warning 
messages.  Post a copy of what you see and some folks here could probably 
help decode it.

At the ">>>" prompt you can type "test 50" (or just "t 50" should work) to 
get a status page.  You should also be able to type "show dev" to see what's 
on the SCSI busses.

The latest NetBSD build (development version) has text support for the 
system's monitor (and keyboard), though if necessary it's also possible 
to use a terminal connected to the printer port as the system console.

Hope this helps - keep us posted on your progress.

Jerome