Just getting started with a MicroVax 3400

From: Chuck McManis <cmcmanis_at_mcmanis.com>
Date: Mon Apr 2 00:35:19 2001

4/1/01 7:33:53 PM, Chad Fernandez <fernande_at_internet1.net> wrote:

>
>The 2 RF35 (I think that's the number) don't have the cables hooked up
>for the panel. I assumed they didn't use the panel. Am I wrong on
>this? They look like later, more modern drives to me, so I thought they
>wouldn't use the panel, and I didn't see any place to hook them up. The
>drive mounted lights do come on.

They should use the panel. There is a 10 pin header that is nestled between
the power plug and the 50 pin DSSI plug, that is where a 10 pin cable
goes from the drive to the back side of the disk bulkhead. That also
sets the unit numbers for the drive. Perhaps someone set them up to
override the unit numbers because they were short of plugs or something.
When you type 'sho dev' they show up as DIAxx what numbers do the
drives show up as?

>Mine seems to have a standard 4 connector cable. If I made a cable, how
>many memory boards could I use?

As many as you can fit, however the CPU is limited to addressing 64MB of
RAM so you can't get more than that. Also the 4MB disables itself if you
install a full 64MB (4 x 16MB is common)

>> The 4Plex should work fine on it, *if* you have a SCSI interface in there.
>
>Good. What should I look for in a SCSI card?

Existence. :-) Actually SCSI cards for this beast aren't hard to find, they are
just hard to afford for many collectors. You want a SCSI card with an 'sbox'
handle. Examples are the Emulex UC-08, CMD CQD-223, etc. I prefer the
CMD ones but Emulex, Dilog, and others made them.

You can buy them all day for $500 each from DEC resellers. On Ebay they
go for less than $300 usually, and of course if you buy a couple of tons of
VAXen before they get scrapped you can often salvage one or two. I sold
one as part of a cherry 4000/200 and now I kinda wish I hadn't (I just got
a VAX 4000/700A that I _really_ would like to put a SCSI drive on.)

If you get one with non-Sbox handles you will either have to adapt a
blank Sbox "bar" to mount the connector or you will have to run the
cable out from between the bars. I've done both.

Alternate mechanisms to getting a SCSI CD-ROM are to get an RRD40
controller (slow but it works!) You may be able to find a DEC reseller who
will sell you the drive and controller for less than $100.

> When I do get a SCSI
>card, should I remove the TK70, or just mount the cd-rom in an external
>case? I would like the cd-rom internal, but I don't know how important
>that TK70 might be.

No doubt the TK70 will be critical if you find a piece of software that only
comes on the original TK50 media. I prefer my VAXen to sport a TKxx
drive. Something I've been doing lately is making 'vax boxes' which are
2 unit SCSI cases with a VAX compatible CD-ROM drive and a removable
SCSI drive. Then I get a couple of trays for the SCSI drives (these are pretty
cheap these days) and put VMS on a 200 - 500Mb SCSI disk and NetBSD
on a 1GB disk (not that NetBSD is that much less efficient, just that I
like room to build kernels and such.) Then one can swap out disks to run
different OS'es.

Mounting the CDROM in the case will be problematic and frankly doesn't
get you all that much.

--Chuck
Received on Mon Apr 02 2001 - 00:35:19 BST