> <I was always told that about the 11/750 as well.  However, we got one that
> <was being discarded by the chem department when I was an undergrad.  We
> <plugged it in, turned it on, and it happily booted VMS from its disk.  Is
>
> I'll bet someone put a tu58 hardware emulator or other mod in there.  If
> there is no tape in a stock 750 it just looks at you.

They can boot tapeless, if you have an appropriate boot ROM. There are four
boot ROMs, and one of them is selected from the 4-way switch on the front
panel. They are actually 82S131's (from memory) which are 512x4 bipolar PROMS,
which appear as 256 bytes to the CPU.  These are relatively simple to get
hold of and burn data into, which is what I needed to do to boot from my
UDA50. I now have boot proms for UDA50/RA81, TU58, RL02, RM05 (and a fifth
one I can't remember). I believe I also have assembler source for them too,
which means new ones could be crafted if need be.

So, if anyone needs fresh '750 boot proms, I could probably arrange to
burn some.

Brian.

--
------------------------------------------------ Jpotherington Bent McRent ----
Brian Murray     brian@proximity.com.au     http://www.proximity.com.au/~brian/
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