[Info-vax] Intel proposal to simplify x86-64

[Simon Clubley]

On 2023-06-05, Dan Cross <cross at spitfire.i.gajendra.net> wrote:
>
> Obviously, if the x86S proposal goes forward, the relevant code
> bits in VMS will have to change.  I suspect VMS on x86_64 relies
> on UEFI or a BIOS for DRAM training, so it can basically ignore
> that; the FIT thing and SIPI startup may be a bit more
> interesting, but fortunately, it's mostly in assembler and
> really only a few dozen instructions so the change area will be
> pretty small.
>
> There are good reasons for wanting to get into 16-bit mode
> (mainly to grab services from a legacy BIOS for e.g. setting
> graphics modes and things like that; pre 3.0 VBE etc) and
> obviously that won't be supported anymore; I doubt it matters
> much for VMS, however.
>

_If_ I understand what you are saying correctly, then that would
appear to mean existing versions of 64-bit operating systems are
not compatible with this proposed new architecture, which means
that you will need a new version of your existing 64-bit operating
systems before it will boot on the new architecture.

Furthermore, it would _appear_ the new version will not run on the
existing hardware. Do I understand the situation correctly ?

_If_ my understanding is correct, then that would cause some real
costs with management of systems in the real world that's going to
really slow down adoption of the new architecture, until people are
forced to switch due to the lack of old-style hardware.

Simon.

-- 
Simon Clubley, clubley at remove_me.eisner.decus.org-Earth.UFP
Walking destinations on a map are further away than they appear.