Subject: Re: MV3100 vs VS3100 for NetBSD use.....
To: None <Robertdkeys@aol.com>
From: Brian Chase <vaxzilla@jarai.org>
List: port-vax
Date: 12/02/2002 22:06:51
On Mon, 2 Dec 2002 Robertdkeys@aol.com wrote:

> Whilst digging thru the pile of dusty VAXentoyz, I noticed that the
> stack of 6 inch thick 3100 boxes fell into two types....1)MV3100 and
> 2)VS3100 of which I have two each.  Afer checking them out I saw that
> the VS3100's had 32mb ram each.  With some head scratching as to
> future uses of these critters (namely as test build boxes), I arrived
> at a question of what is the pro and con of using the MV3100 vs the
> VS3100 boxes in NetBSD?  Is there any advantage to using the KA42
> VS3100 machines over the KA41 MV3100 machines?  IFF, at some time,
> graphics head use is practical, then the VS3100's would seem to be the
> better boxes. Any thoughts on the matter are appreciated.

[For the sake of this discussion, I'm using MV3100 to refer to the older
 KA41 models (i.e. The MicroVAX 3100/10/20/10e/20e and the VAXserver 3100).
 The VS3100 refers to the KA42 models (i.e. VAXstation 3100/30/40/38/48).]

It'll depend on the precise models of each.  One definite advantage the
VS3100s have over the MV3100s is that the VS3100s have an external
secondary cache.  The MV3100s only come with the primary, on chip,
cache.

The published VUPs for the systems are:

  System			VUPS
  -----------------------	----
  MicroVAX 3100 10/20		 2.4
  VAXstation 3100 m30/m40	 2.8
  MicroVAX 3100 10e/20e		 3.5
  VAXstation 3100 m38/m48	 3.8

With the right cabling, and if someone could write a device driver to
support it, the MV3100s can support up to 12 terminals.  By default it
comes with the ports and support for four terminals.  The VS3100s are
the simillar in that they've four serial ports, but two of the ports
are used by the keyboard and mouse.  I've not investigated how easily
the mouse and keyboard ports could be adapted for terminals.

If you get one of the large b&w monitors with the VS3100, NetBSD does
support wscons on the mono frambuffer.  You can have virtual terminals
with that.  If you like really large text screens or really large type,
the text mode graphics console can be a good thing.  This would
especially be the case for people with vision problems.  (An alternative
for straight text terminals would be to get a VT525 and hook a large PC
VGA monitor to it.)

Then both the MV3100 and VS3100 come in various sized cases which I
guess could be termed "thin" and "thick".  I know in my thick MV3100,
there's room and cabling in it for four 3.5" SCSI devices and one HH
5.25" device, OR three 3.5" devices and one HH 5.25" device, and one FH
5.25" device.  In my case (and case), I've got four hard disks and a
tape drive on the internal SCSI controller.  IIRC, the thin cases can
only accomodate three 3.5" drives, one of which tends to be a floppy.
One winning feature of the MV3100 is that their second SCSI controller,
used for external devices, has a standard 50pin centronics connector.
The external SCSI connect on the VS3100s ends in a non-standard variant
of the 68pin connector commonly used on more modern SCSI devices.  This
port is useless unless you've the matching DEC SCSI cable to take
it to a normal 50pin centronics connector.

Ohh, and there are two flavors of VS3100 daughter card, there's one with
two SCSI controllers and one with a SCSI and an MFM controller.  I
personally find the dual SCSI controller more useful.  I've only ever
seen them in the VAXstation 3100/m38&m48s, I think all the VAXstation
3100/m30&m40s came with SCSI/MFM, but I did verify that a transplanted
SCSI/SCSI worked just fine in a VAXstation 3100/m30.  AFAIK, all of the
MV3100s have dual SCSI controllers, which sadly aren't the same as the
VS3100 ones.  The memory boards seem to be interchangable, however.

The permutations available are so numerous that I don't think anyone can
really say there is a *best* system out of the lot.  It really depends
on what you want in the box.  My vote is for a "thick" MV3100, packed
with SCSI HDs, four terminals, and 32MB of RAM.  That's close to what I
have now, with the exception of the system only having 16MB of RAM.

If you're looking to compile stuff, get systems with as much RAM as you
possibly can (32MB max on all the models discussed here).  It also helps
to spread out your I/O across multiple disks or even to the network.

-brian.