Klaus D. Witzel wrote:
> On Tue, 08 Aug 2006 16:53:46 +0200, Howard Stearns wrote:
>
>> Imagine that a magic fairy comes and creates a system that works 
>> exactly as you prescribe.
>>      Now, how will you or your users guess that 64MB RAM / 100MB disk 
>> / 100MB traffic/day is appropriate for one application, while others 
>> use different figures?
>
> Would you say that the above is any different from a single computer 
> system with exactly the capacity limits you gave? If so, mind to explain?

I agree that they're the same. And I would never order a computer saying 
that it must not have more than 64MB, 100MB disk, nor allow more than 
100MB traffic/day. Nor would I attempt to implement "safety" that way on 
a single or partitioned computer.

>
> BTW: in ancient (computer age) times we had to implement contingency 
> systems (sometimes mistakenly called accounting systems) because there 
> was only one computer for 1,000's of users, like for example here:
Indeed, and there is good reason that computers are no longer 
implemented that way.

While I certainly don't feel that "no body does it that way" is a valid 
argument that something should not be done, I do feel it is instructive 
to note that, while there are many projects to build distributed systems 
that allow resources to be shared among computers, the opposite does not 
appear to be true (e.g., hardware systems that segregate or cap resources).

It's rather suspect that the original project spec of how to limit 
resource use on a single processor should come out of a problem in 
distributed computing, which by definition is an attempt to gain overall 
system power and access by sharing resources between computers. There's 
a good heuristic: Don't create a feature requirement that contravenes 
the overriding project goal!

>
> - http://www.unibw.de/
>
> on a B7800/B7900, the successor of the B5000.
>
> /Klaus
>
Thanks for making my point!

-- 
Howard Stearns
University of Wisconsin - Madison
Division of Information Technology
mailto:hstearns at wisc.edu
jabber:hstearns at wiscchat.wisc.edu
voice:+1-608-262-3724