HAC2GM::TOCCL1::FERRIBY@ATHENA.HAC.COM (John.D.Ferriby@athena.hac.com, (06/06/88)
> 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 //////////////////////////////////////////////////////////////////////////////// / 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 / ////////////////////////////////////////////////////////////////////////////////
nagy%warner.hepnet@LBL.GOV (Frank J. Nagy, VAX Wizard & Guru) (06/09/88)
>> 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 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. ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ is <left out paragraphs on DEUNA 'bootable' switch and 'tertiary' and 'secondary" loaders, etc.> > ... 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?] The reason the MicroVAX-II (or -3000) can be booted across the network is that the boot PROMs support the DEQNA as a boot device for the 'secondary' boot code. The primary boot code (known as VMB.EXE on *big* VAXes) lives in those ROMs on the MicroVAXen. There has to be explicit support in the boot ROMs for network boots. The 750 ROMs do not have the necessary code to boot from a DEUNA or DELUA. From some old conversation I had, I understand that the 750 boot ROMs are too small for such code to be added. It *might* (repeat: MIGHT) be possible to write a version of VMB.EXE to boot a 750 across the network. The 750 would then have to be setup to boot VMB from the TU58 (real *s*l*o*w*l*y*) AND again you'll probably have space problems since a TU58 does not have a great deal of space. In either case, this is *not* a trivial task. And without ROM support for network boots, 750's can't be LAVC satellites. However, you should be able to make multiple 750's be LAVC members by having each LAVC be a boot node with its own local system disk. You'll have to play with the cluster parameters (VOTES and QUORUM) to get it to work correctly and avoid a partitioned cluster, will have to understand what you are doing since what you do will be *UnSupported* by Digital (that means they'll not be too sympathetic or helpful if you have problems - it does not necessarily mean that it *won't* work, it just takes more expertise and the will to succeed - or the guts to bull ahead through the obstacles). = Frank J. Nagy "VAX Guru & Wizard" = Fermilab Research Division EED/Controls = HEPNET: WARNER::NAGY (43198::NAGY) or FNAL::NAGY (43009::NAGY) = BitNet: NAGY@FNAL = USnail: Fermilab POB 500 MS/220 Batavia, IL 60510