[Info-vax] rx2800i2 sales/support window changes

[Keith Parris]

On 2/13/2014 4:03 PM, JF Mezei wrote:
> Considering VMS is limited to Tukwila tech (which is already a few years
> old), I suspect that x86 emulated solutions will be competitive quite
> soon in terms of performance (if not already).

Think a little harder about the difference between native execution and 
emulation and how much overhead is involved in emulating a different CPU 
architecture, even if you use the most-efficient technique available 
today of binary translation of blocks of code.

Truth is, it takes probably at least a decade or more of system 
performance improvements for an emulated platform to equal the 
performance of the original hardware. That's why people can be happy 
with the performance of VAX emulators today, 14 years after the last VAX 
was sold (from looking at their website, it appears Stromasys feels 
comfortable replacing systems as big as a VAX 7000-660).

But from what I've heard from customers, it's not yet practical today 
for someone with, say, a 32-CPU GS-1280 (or generally even a 4-CPU ES45 
or ES47) to get equivalent performance on an Alpha emulator even on the 
fastest x86 box (although from their website, Stromasys appears 
perfectly willing to replace up to a GS-320, which was announced 14 
years ago, and even a GS-1280, which last sold new 7 years ago).

> The danger is that if an IA64 emulator is done, it will emulate Poulson
> which is not compatible with VMS. We know that existing Alpha emulators
> are compatible with VMS.

Anyone who takes the time and expense to write an IA64 emulator would 
presumably be looking at their potential market, and would thus be 
unlikely to decide to emulate only Poulson (or Kittson) processors and 
thereby exclude their largest initial market, OpenVMS customers.

> That leaves the rhetorical question of whether a x86 emulating Alpha
> instruction set would yield better/equal/worse performance than the same
> x86 emulating the IA64 instruction set.

Since HP Mature Product Support for OpenVMS 8.4 on Alpha is committed 
only through at least the end of 2018, whereas MPS on OpenVMS 8.4 on 
Integrity is committed through at least the end of 2025, anyone 
interested in longevity of support would probably aim to get to 8.4 on 
Integrity.