[Info-vax] OT: IA-128 ???

[glen herrmannsfeldt]

Arne Vajh?j <arne at vajhoej.dk> wrote:
(big snip)
 
> A VAX is 32 bit because the application use 32 bit virtual addresses.
> Physical addresses is something else.
 
> I can not comment on PDP-11.
 
> I seem to recal that physical addresses of later VAX'es were bigger
> than 32 bit, but 40 bit sounds too much - that would be 4 TB of RAM.

I have sitting here the "VAX Architecture Reference Manual"
which includes specifications for some VAX.

The last one here is the 8800.  The "Physical address space" is,
of course, 32 bits, but only 29 bits address installed memory.
Above that is BI#0, multicast, boot ROM, reserved, node private space,
reserved, node 0 through node 15, reserved, BI#1 through BI#3, and
then more reserved.

So up to 512MB of actual memory.

-- glen