On Sun, Apr 08, 2001 at 01:28:09PM +0200, Thomas Michael Wanka wrote:
> And it is more likely, that IBM will supply CPU modules (hot 
> swappable of course), to enhance the performance of the S/390 in 

The z/900 machines (64 bit) come with 20 processors in an 25-sq-in
MCM. More than one of these boards can be installed. In the event a
CPU has a temporary error it will backup to the last checkpoint and
retry. If the CPU is really bad then the work fails over to another
processor without disrupting the program running. 

That's better than just hot-swappable, and I wonder if any other
system can do the same trick. Can any other processor (Alpha, MIPS,
SPARC) failover to another CPU nondisruptively?

On the CPU-power/cost front, you only pay for the CPU power you need.
Meaning you get excess power that is disabled until you call IBM, get
a key, and enable it on the fly. 

> a later time and even if Sun could deliver 500 CPUs for a lower 
> price, you needed to shutdown every system for the upgrade, and it 
> probably will take weeks of labour to upgrade all 500!
 
> I defenitely would preferr the netra solution, but the S/390 could be 
> the more economical.

Well, yeah, true. I'd agree with that except I prefer Alphas. :)
I still miss the AlphaStation 400 I had on my desk for years...
Logging into a VM system and getting NetBSD instead of CMS would
be a nice compromise, though.
-- 
"A method for inducing cats to exercise consists of directing a beam of
invisible light produced by a hand-held laser apparatus onto the floor ...
in the vicinity of the cat, then moving the laser ... in an irregular way
fascinating to cats,..." -- US patent 5443036, "Method of exercising a cat"