Re: Larger memory option for VAXstations

[Miod Vallat <miod%online.fr@localhost>]

> Is there an even more recent VARM out there?  Or is this a retcon on a
> previous version which _did_ have 23-bit PFNs?  I have a paper VARM
> from years earlier (1982?), but it's still packed away from my move, so
> I can't easily check it.

There was a `second edition' VARM edited in 1990 and released in 1991.
It mostly differs from the first edition by documenting the vector
extension in the new chapters 12 and 13, and an annex B covering 37
different system models in the B.2 section.

It also describes the 21- and 25-bit PFN layouts in chapter 4, but does
not describe which systems use 25-bit PFN and how to enable this mode on
systems which support both flavours. This is only documented in
system-specific manual, such as the PAMODE IPR in the ``VAX 7000/10000
KA7AA CPU Technical Manual'', EK-KA7AA-TM.