Path: utzoo!attcan!uunet!lll-winken!lll-tis!helios.ee.lbl.gov!pasteur!ucbvax!ATHENA.HAC.COM!"HAC2GM::TOCCL1::FERRIBY"
From: HAC2GM::TOCCL1::FERRIBY@ATHENA.HAC.COM (John.D.Ferriby@athena.hac.com,
        524-8197 or 8-224-8197, 313)
Newsgroups: comp.os.vms
Subject: One piece to the LAVC/750 puzzle...
Message-ID: <880605194528.20203C0D071@athena.HAC.COM>
Date: 6 Jun 88 02:45:28 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 39

> Some friends would like to set up a LAVC which includes 750s as satellite
> nodes that boot form a system disk on the LAVC boot node.  Presumably, one
> would need either a boot PROM or a suitably configured TU58 with an
> appropriate boot program (such is used to boot 750s in a CI cluster).

I have this inkling that tells me that following the NI [LAVC] path instead of
the CI path will be more fruitful.  I would think that it would be possible
to make a 750 look like a MicroVAX II or PDP/Gateway without too much sweat.
It may again be a very nontrivial task.

I'm fairly sure that the 'bootable' switch on the DEUNA will have to be
toggled.  This is the standard case for PDP's running gateway software.
An FE, [not our regular, onsite one, someone else...] mentioned that he
had seen it done, and the switch setting was required.  Your FE probably
is at least aware of the switch.   From there, it is just a matter of trying
to fool the loader software I suspect...  

The 'secondary' loader will load the on-board memory of the DEUNA, you should
be okay there.   The 'tertiary' loader will then be loaded into a section
of the requestor's memory.  From there the O.S. is loaded.  [This is how
it works on SFGs, DECSAs, etc...]  I know that the DEUNA/DELUAs have different
loaders, but how about the DEQNAs?  You may need to borrow a DEUNA secondary
loader from one of your DECSA boxes...  There again, if you run MicroPower
Pascal, you could borrow the loader that runs with that for a MicroPDP 11/73.
(?)  Certainly many options here....   There may be some serious tricks involved
in fooling the 'tertiary' loader.   A cursory comparison of the exact
differences between 750 and MicroVAX II architecture should be an indicator.
[Yes, there are some *BIG* differences, but will it matter?]

Hope this helps,

John

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/  John D. Ferriby                    Corporate DECnet: TOCCL1::FERRIBY        /
/  Software Systems - Networking                     -or- 2056::FERRIBY        /
/  EDS - Plant Automation Division    Arpa: FERRIBY%TOCCL1.GM@HAC2ARPA.HAC.COM /
/  300 East Big Beaver                                                         /
/  Troy, Michigan  48007-7019                                                  /
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