Article 48380 of comp.sys.dec:
In article <5d8ejf$1aom@news.ccit.arizona.edu>,
Gordon Zaft <zaft@ece.arizona.edu> wrote:
>
>	I just acquired a couple of VAXstation 3100s (I believe they are
>model 30s).  I have a number of questions I'm hoping someone can help me
>with...
>
>	They both came with RZ22 disks, which are apparently about 50
>Mbytes and therefore can't possibly have VMS on them.

It's possible, though unlikely.  Most likely the 3100's were
satellites and the RZ22's were used for local paging and swapping.

>  I was able to 
>switch one of them to use the console port, hooked up a terminal and
>was able to boot it down to 1.  They both have an RX23 floppy.
>
>	1) Neither one of them actually have the RZ22 hooked up to
>anything; there's not even a ribbon cable connected to it.  There is a
>funky-looking connector right next to the IDC connector that goes to the
>floppy; is that where the internal disks connect?  It's strange-looking
>since the pins (I think it's a 50-pin) look like the high-density scsi-2
>connectors on the back.  Can I get a cable for this at my local electronics
>store or is it a DEC weird cable?

That internal connector is 100 pins.  The 50-conductor
cable that connects to it loops
to the internal disk drive, and then back again to meet with the
termination resistors on the board.

>	2) One of them has two additional connectors on the top PC board,
>which aren't connected to anything.  What are they for?  I didn't get
>a chance to count the pins on them.

If you have a model 30, they're 34-pin and 20-pin.  They can connect
to an internal MFM winchester that appears to the system as DUA0 or DUA1.

>	3) If I were to buy VMS for this what would I ask for?  I'm not
>always so sure of just calling up DECDirect and having them figure out
>what I need for such an old beast.  Obviously I'll have to get an external
>CDROM or tape to be able to boot this machine.

To connect an external drive to the SCSI bus, you'll need the cable
that plugs into the 68-pin CHAMP high-density connector on the back.  A
BC09J-03 cable from DECdirect ought to do the job (assuming they're
still available.)  You'll also need the SCSI bus to be properly terminated
inside the box; I'm not sure what the cable number for doing this is.

Tim. (shoppa@triumf.ca)