More stuff from the Sun rescue

Doc Shipley doc at mdrconsult.com
Tue Oct 30 11:09:06 CDT 2007


Chuck Guzis wrote:
> On 30 Oct 2007 at 10:19, Sridhar Ayengar wrote:
> 
>> Refresh my memory how those worked?  Two processors in lock-step?  Three 
>> processors in a voting quorum?
> 
> Nothing that simple.  Special software and hardware.  As was driven 
> home to me by a Tandem engineer who was also a good friend, the term 
> of art used by Tandem is "Nonstop" not "Fault tolerant".  A world of 
> difference between them.  For a very good analysis, check out the 
> paper "Why Do Computers Stop and What Can Be Done About It?" by 
> Tandem's Jim Gray.  It should be somewhere on the web, given its 
> importance.  It describes in very eloquent terms, the Tandem 
> philosophy.

   For a very graphic example of that philosophy, consider this:

   In mid-2004 I ran into a guy who works at HP/Austin.  His team had 
just finished a major project.  They had just completed certification of 
the first 10/100 ethernet driver for Non-Stop OS.


	Doc Shipley



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