Odd Q-Bus questions 18/22bit

From: Zane H. Healy <healyzh_at_ix.netcom.com>
Date: Tue Aug 18 10:44:42 1998

>As far as I know, all DEC versions of the VT103 came
>with an 18 bit backplane for the QBus. If an LSI-11/03
>is used, I understand it may be ill advised to make any
>changes in the backplane, as well as fruitless, since this
>CPU can use only a maximum of 56 KBytes of memory
>in any case.

This is what has me worried at the moment. As near as I can figure out,
what I"ve got here is an actual VT100 that has a LSI-11/03 backplane put in
it. I suspect that this was a third party modification and was sold this
way, as two of the boards are from ARC, and the VT100 has a ARC tag on it.
What I'm really wondering (and have mentioned in a previous post) is what a
ARC DFV-11A is, as it's apparently one of the boards that was in the
computer. It looks like when it's fully put together it might have a
whopping 8 or 16k.

I was planning to try using a DILOG controller I've got for a couple of
floppies, but in reading through some stuff I see that the /03 is
apperently a 16-bit backplane, while the card I've got is for a 22-bit
backplane. Is this correct? This card falls into the catagory of really
nice, don't want to blow up :^)

Based on what I've got, I think I'm out of luck for anything fancier than a
/03 in this terminal. Unfortunatly there doesn't seem to be a SLU with the
cards that were in the Box labeled "VT100", and the whole pile I got this
weekend is lacking in SLU's, so this will have to wait till I can get the
parts to manufacture a cable for the one SLU that came with the rack mount
/03's I got.

                                Zane

| Zane H. Healy | UNIX Systems Adminstrator |
| healyzh_at_ix.netcom.com (primary) | Linux Enthusiast |
| healyzh_at_holonet.net (alternate) | Classic Computer Collector |
+----------------------------------+----------------------------+
| Empire of the Petal Throne and Traveller Role Playing, |
| and Zane's Computer Museum. |
| http://www.dragonfire.net/~healyzh/ |
Received on Tue Aug 18 1998 - 10:44:42 BST

This archive was generated by hypermail 2.3.0 : Fri Oct 10 2014 - 23:30:44 BST