🚀 go-pugleaf

In article <6374@amelia.nas.nasa.gov> yamo@wk46.nas.nasa.gov (Michael Yamasaki) writes:
>Greetings.  IMHO, one of the places where supercomputers (my only experience
>is with Cray 2 and Cray YMP) excel over the touted killer micro solution
>is in I/O performance.  
>
>My workstation (a Personal Iris) gets something less than a megabyte/second
>disk I/O.  Our Cray 2 gets something more than 10 megabytes/second.  

There are some true "killer micros" that address I/O issues on the market
right now.  BBN's newer "Butterfly" machine (TC2000) can be configured with
one I/O bus (read VME) for about every TWO processors.
About three quarters of these busses are single slot, the rest being 4-slot 
buses.  VME-to-SCSI adapters and VME bus repeaters are available.
Note that these busses are NOT used for direct communication
between the processors.  There is a Butterfly interconnection network for that.
These busses communicate with memory at a peak of 8 Mbytes/sec.  

Using a crude test of "dd if=<unbuffered device> of=/dev/null" and some 
blocking arguments currently yields about 1 Mbyte/sec using the unbuffered 
device.  This single threaded I/O rate is similar to that found on the IRIS 
above.  Distributing files and users across multiple disks allows you to 
effectively multiply this bandwidth.  The kernel, including the disk device 
driver, is fully parallel.  In addition, paging traffic can be easily 
distributed across separate disks.  All of this capability is available NOW.
One existing customer has 9 disks on five I/O busses.

This amount of I/O is starting to look reasonable for a killer micro.
Some work remains to be done, however, in getting the software to effectively
use all of the bandwidth.

I believe that Alliant has a similiar (though not quite so scalable) story.
The rumor mill has NCUBE and Intel developing similar capabilities for their
machines.

#include <std_disclaimer.h>
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Laurence S. Kaplan		|    \ 0 /    |		BBN Advanced Computers
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