[Twg] Updated draft requirements posted to discuss

[John Carrier]

Dave Dillow wrote:
> John, can you explain some of the driving forces behind the 10 billion
> files in a directory -- how does one plan to work on such a system; will
> it be expected to be POSIX compliant?

This is an HPCS requirement.  Note that this was a prediction of capacity needs made in 2006 for system that was to have been delivered in 2010.  Though the mission partners were pretty good at guessing how I/O would have to scale, some of their requirements are still a stretch today. 

--jc