[Info-vax] VMS port to x86

[Keith Parris]

On 3/24/2012 7:38 AM, John Wallace wrote:
> On Mar 24, 12:45 pm, "John Reagan"<johnrrea... at earthlink.net>  wrote:
>> "JF Mezei"  wrote in message
>>
>> news:4f6d5a90$0$2201$c3e8da3$460562f1 at news.astraweb.com...
>>
>>> I was just thinking.
>>> If HP were to produce fault tolerant 8086s for NSK, those boxes could
>>
>> Any more fault tolerant than the Itaniums used by NSK today?
>
> Exactly.
>
> Tandem hasn't needed CPU lockstep since they dropped their own
> proprietary processor architectures, and that's a LONG time ago in
> processor history. This isn't a secret, but it may as well be as far
> as the trade media and others are concerned.
>
> In modern Tandem boxes, the synchronisation is not at instruction
> level or even main-memory access level but conceptually more like "IO
> access level" (or maybe process context switch level). The
> synchronisation is not on the CPU chip, not even particularly close to
> it, but is managed by a piece of complex external logic called the
> Logical Synchronization Unit, which doesn't care about instruction-
> level lockstep but does care that each processor's operations result
> in the same IO with the outside world (and the same context if a
> processor swap has to occur). The LSU also does a lot more than that,
> which I won't go into here.
>
> The 2006 Oztug presentation at [1] was given by one of Tandem's senior
> architects, Hal Massey, and was an excellent intro to the internals of
> Tandem boxes over the years. Sadly, it's fallen off the internet and I
> haven't kept a copy and nor have I yet been able to find a suitable
> replacement. Suggestions welcome for a definitive replacement - but
> I'm not holding my breath.

> [1] www.oztug.org/events/2006/AdvancedArchitecture_Massey.pdf - now
> vanished, sadly.

I see the session description for Hal Massey's session at Archive.org:
http://web.archive.org/web/20060716110540/http://www.oztug.org/events/2006/Techsessions.cfm

"NonStop Advanced Architecture for Integrity NS Server, Hal Massey, HP

The NonStop Advanced Architecture (NSAA) is a new offering in the 
NonStop world. It's so new that we are finding new ways to describe it, 
new aspects of its advantages, and positve feedback from customers who 
are utilizing it in their applications on Integrity NS-series servers. 
The fundamentals that the NonStop division is famous for are showing up 
in exciting new forms and functions. This is the session to learn about 
how NSAA can make a difference in your world."

Does sound interesting. Maybe some of these will be helpful:

HP NonStop Advanced Architecture web page with FAQs and white paper:
http://h20223.www2.hp.com/NonStopComputing/cache/77119-0-0-0-121.html

NonStop Advanced Architecture, System Configuration and Site Planning, 
Bob Kossler
ftp://ftp.hp.com/pub/nonstop/ccc/2005/jun0905.pdf

The NonStop Advanced Architecture Value Proposition: HP Integrity 
NonStop Server Availability Compared to NonStop S-series Server, Bob Kossler
ftp://ftp.hp.com/pub/nonstop/ccc/2005/sep1505.pdf

Data Integrity in HP NonStop Servers
http://www.cs.uiuc.edu/class/sp06/cs523/nonstop-selse06.pdf

NonStop Advanced Architecture
http://www.cse.chalmers.se/~davidwh/eac/papers/karlsson5.pdf

NonStop Servers - The future    (from 2003)
http://www.suntug.org/Articles/SE_RUG_Roadshow_V3_June_203.pdf