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

[Roger Ivie]

On 2009-10-18, glen herrmannsfeldt <gah at ugcs.caltech.edu> wrote:
> Arne Vajh?j <arne at vajhoej.dk> wrote:
>  
>> 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.

They added some bits in later models. IIRC, they took over the
"reserved for software" bits in the PTE and made them physical address
bits. It wound up being 35 bits or somesuch.
-- 
roger ivie
rivie at ridgenet.net