[Beowulf] massive parallel processing application required

Jim Lux James.P.Lux at jpl.nasa.gov
Fri Feb 2 06:19:47 PST 2007


At 12:57 AM 2/2/2007, Geoff Jacobs wrote:
>Jim Lux wrote:
><snip>
> > (If I go with the FiOS offering though, that may prompt
> > some re-evaluation)
>Why? Only a third of the bandwidth of fast ethernet at peak speeds
>(which you aren't going to see). Hell, an rtl8139 could handle that.
>
> > Likewise, a small business with half a dozen or a dozen desktops and a
> > couple servers isn't going to see a huge benefit from faster networking,
> > because they're throttled by the server's disk speed, more than anything
> > else. (assuming they're not hosting a big website, etc.)
>More likely throttled by the operators.


The operators of the desktops, I assume.  The business offerings have 
commited information rates, etc.




> > So, you're looking at GigE making a difference in two areas:  replacing
> > cable TV (all those 20 Mbps HDTV streams) and in big companies.  But
> > even in big companies, GigE to the desktop doesn't necessarily buy you
> > much, if you're all competing for the same server resources.
>Certain areas, such as digital video content development, are much more
>accessible with high speed interconnect going commodity. However, very
>few companies have the concentrated, high volume databases which would
>really tax a network.



One comment the guy from ATT made back in the 90s was that it's 
impossible to predict what really might happen when you do have real 
ubiquitous high speed access to the desktop (which is only just now 
becoming available, in the sense that the network connection is 
faster than the disk or CPU). It's that paradigm shift thing. The 
current software model and the conceptual models of the vast majority 
of application developers (or users who want things done) tends to be 
framed by the assumption that network access is slow and/or 
expensive(hence my comment about having everything locally)

If you have a very fat, low latency, cheap pipe, all of a sudden, 
there are classes of applications (some of which we, by definition, 
cannot anticipate) that might become possible.  For instance, the 
vision of "per use pricing" for office tools with very thin clients 
becomes possible.  With a fat pipe, you could go back to the 60s 
timesharing model, with the desktop being just a display and a keyboard.

Jim 





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