[Info-vax] Kermit on Itanium VMS

[Arne Vajhøj]

On 31-12-2009 17:39, Bill Gunshannon wrote:
> In article<CkTD8HhjfW7c at eisner.encompasserve.org>,
> 	koehler at eisner.nospam.encompasserve.org (Bob Koehler) writes:
>> In article<Qrmdnbi9nf6YIabWnZ2dnUVZ_jxi4p2d at giganews.com>, "Richard B. Gilbert"<rgilbert88 at comcast.net>  writes:
>>> Err. . .  How about RSX images in compatibility mode on a VAX 11/780 or
>>> 11/750?
>>>
>>> After all these years I have a little difficulty imagining why anyone
>>> would want to but given sufficient incentives it's possible to do it.
>>
>>     Is the RSX AME still supported under 7.3?
>>
>>     If so, then, yes, it may be possible to run a 40 year old binary
>>     on the latest VMS for VAX.
>>
>>     But that depends on the definition of "run".  The AME added
>>     compatability mode emulation when the first VAXen without
>>     compatability mode shipped.  I'm fairly sure you could also get
>>     40 year old images to run on SIMH on just about any platform.
>>
>>     So if I have SIMH simulating a PDP-11 on an Itanium, am I "running"
>>     40 year old images on the latest VMS for Itanium?
>>
>>     Or do we require hardware execution of the instructions to at least
>>     the extent that VAX-11 series microcode implemented compatability
>>     mode instructions?
>
> And, once again, people here have completely missed the point.  IBM
> (and I am pretty sure UNISYS) have maintained that compatability from
> the very beginning with no breaks in between.  We are not talking about
> someone coming along after the fact and writting an emulator but the
> original company thinking that backwards compatability was necesary
> enough to build it into their products even after the original
> hardware ceased to exist.  We are not talking about "VESTING", we
> are talking about just plain running old programs.

DEC could have kept PDP-11 compatibility mode in all VAX'es and have
added both PDP-11 and VAX compatibility modes to Alpha.

But I doubt that it would have been worth the cost.

The VMS market is not like the IBM mainframe market.

And UNISYS is mostly selling services and x86-64 servers with
Windows and Linux today.

Arne