> On October 29, you wrote:
> > <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.
> 
>   Yes...the 750 loads microcode from the TU58 when it starts up...It
> doesn't even know the full VAX instruction set until it spins that
> tape, as I understand it.
> 
That's a misunderstanding. A 750 have the full 11/750 instruction set
in hardware. But due to bugs in the microcode DEC provided software
patchable microcode updation through TU58. A 750 needs at least uCode
level 95 to understand the 8MB memory controller IIRC, and at least
uCode level 98 to understand 14MB of memory. Most 750's were hardware
upgraded to at least uCode level 95, meaning that any OS will run nicely
on an 8MB machine (I did this for years) without any external loaded
control store. A file with uCode level 98 is included in the NetBSD
distribution, the boot program will patch your system if it finds it
necessary.

-- Ragge