LSI-11/2

From: Patrick Finnegan <pat_at_purdueriots.com>
Date: Fri Jul 5 07:08:51 2002

On Fri, 5 Jul 2002, Andreas Freiherr wrote:

> Patrick,
>
> your BA11-M box (if it is the one from the video effects box you
> described earlier) is probably the second-smallest Qbus box. There is
> one with a backplane half as wide as yours, so you can put in only four
> dual-height modules. This is the BA11-S, aka shoebox. You lost your bet
> ;-)

I sort of meant address bus width, not physical size, but yeah, it's
pretty small size-wize too.

> That ESDI controller (seems to really be ESDI, and not made by DEC), it
> does not possibly happen to carry the proper boot ROMs around with it? -
> Some third-party Qbus disk controllers do, but you may need different
> ROMs or jumper settings for VAX or PDP-11 use.

It has a ROM on it labelled "SDC-RQD11/EC 100097-0100E", but if it's a
boot rom, it's definately has VAX code in it. On the other hand, the
controller does do MSCP, so I should be able to use anything that
can boot from an MSCP device, right? Unfortunately, it has no port for an
floppy drive (RX50/RX01/RX02/etc).

> > > >First, however, I'm sure I need DEC boot roms for it, or some other way
> > > >to get boot code into it. Does anyone happen to have some laying around
> > > >they could maybe send me an image of? Also, I'm on the lookout for a
> > > >RLV12 and berg cable to connect to the RL02 I have sitting around here..
>
> What ROMs you need may depend on the card (MXV-11, TEV-11, ...).
> Unfortunately, I don't think I have any spares. However, since you have
> a ROM board (hopefully, it can be convinced to decode the chip selects
> to the right address range...), you may simply burn one of the publicly
> available bootstraps into suitable chips. That's not a lot of wizardry,
> once you know which device you want to support. It becomes more
> difficult if you want to offer a choice to the operator, which is what
> DEC's ROMs sometimes do...

Not a big concern to me really...

> Same for the RLV12: quite a good choice, given that you already have a
> suitable drive, but no parts available from me. The older RLV11 would
> not help because it needs CD wiring to interconnect the two boards it
> consists of. The cable is not too critical at the controller side: get
> any ribbon cable from your local store, perhaps they will even be able
> to put the connectors on for you. But, they will certainly not have the
> matching connector for the drive. BTW, do you have the bulkhead
> connector for transition from the ribbon cable to the round drive bus
> cable, and a terminator for the drive bus? (The terminator looks like a
> connector with no cable attached, has a resistor array inside.)

All I have is the physical RL02 drive and one disk pack. I even had to
splice on a new power cord when I got the thing from Purdue. No cables or
terminators (or controllers, unfortunately) were to be had. Does anyone
have an RLV12? I'd be willing to pay *some* money for it, but can't
afford the going rate on ebay probably.

> > I've got a DECNA (i think) network
> > adaptor in my VS3200 I could try to use. Right now, I'm wanting to try
> > and re-use hardware I have instead of search for hardware that is hard to
> > find.
>
> Sure, you can expand later. That's what these boxes are made for.
>
> If your network interface is plugged into a Qbus, it must be a DEQNA or
> a DELQA (if you cannot find the M numbers through Google, look at the
> board: the letters must be printed on it somewhere, etched in copper).
> The DECNA is for the Professional machines (desktop PDP-11, as in Pro
> 350 or Pro 380, seen lately in this mailing list). The DEQNA is the
> older board, which will not work in a VAX with VMS versions later than
> V5.something. For PDP-11 use, either a DEQNA or DELQA will do, but
> you'll need sufficient memory to support a network interface and
> protocol stack.

I'm not to worried right now. It also appears to actually be a DELQA-M
(M7516). Oh well, I can use it if I get any more QBUS vax stuff.

> > Also, is it possible/easy to change the M8044-BB board (8KW?) to have at
> > least 16KW if not 32KW of memory? That'd be a nice upgrade for the
> > machine if I can do it myself with 'stock' DRAMs.
>
> I have no docs available here in the office, but I seem to remember that
> the M8044 (MSV-11?) was available in several flavors (identified by the
> letters after the dash) with different capacities, so it might be
> possible. I'll look up more about this at home. There should be boards
> to examine. Stay tuned.

Yup, from 4kW to 32kW, there's some description of the differences here:
http://www.not-compatible.org/PDP-11/modules/msv11-d.html
However, it doesn't tell me what I need to look for in a RAM IC for it,
like if a standard 4116 or 4164 will work (possibly grounding extra
R/C address lines on the 4164...) There's a total of 32 memory IC's, all
non-standard looking part numbers on the MSV11 I have.

> I think Megan was thinking of a pretty comfortable machine, while you
> first need to get started at all, after yanking the PDP-11 from the
> video effects processor it was embedded in. Since I also started with a
> rather small configuration, but have meanwhile grown to a total of three
> PDP-11s (one UNIBUS, two Qbus) to fill a room, this must be possible for
> you, too.

That's the basic idea I had.

> A remark about the power supply in your BA11-M: it is switch mode, but
> does not require a minimum load current. With very low output currents,
> it runs as a linear regulator, and with increasing load, it starts
> switching, but with the load further increasing, it will slowly loose
> efficiency (read: get hot). I try to keep mine only fairly loaded to
> extend their life.

Intersting, I'll keep that in mind. Thanks for the help!

-- Pat

> --
> Andreas Freiherr
> Vishay Semiconductor GmbH, Heilbronn, Germany
> http://www.vishay.com
>
Received on Fri Jul 05 2002 - 07:08:51 BST

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