Re: backward architecture, The Design of Design

anton@mips.complang.tuwien.ac.at (Anton Ertl) writes:

Michael S <already5chosen@yahoo.com> writes:

On Thu, 9 May 2024 08:19:39 -0000 (UTC)

The term comes from Brooks.  Specifically, he applied it to the
S/360 line of computers which had a very wide performance and
price range, and programs (including operating systems) were
binary compatible from the lowest to the highest performance and
price machine.

>
>
I suppose, it means that my old home PC (Core-i5 3550) is downward
compatible with my old work PC (Core-i7 3770). And my old work PC is
upward compatible with my old home PC.

>
Given that both use Ivy Bridge CPUs, there is no compatibility issue
as far as the CPU is concerned.

Actually, there are cases where this is not true: Intel sabotages
upwards/downwards compatibility by disabling architectural features on
cheaper models (in particular, they disabled AVX on Ivy Bridge CPUs
sold as Pentium G or Celeron G).  But for your Core ix-based Ivy
Bridges, AFAIK there is no such problem.

- anton
--
'Anyone trying for "industrial quality" ISA should avoid undefined behavior.'
  Mitch Alsup, <c17fcd89-f024-40e7-a594-88a85ac10d20o@googlegroups.com>