Brief article on benchmarks of Python repository with leading DVCSen

[Nicholas Allen]

> I'll also mention that in many cases /tmp is a different filesystem. And
> as such, branching into /tmp will not be cheap for other system either.
>
> Similarly, branching C: => D: is not cheap, because you cannot hardlink
> between filesystems.
It's still cheap compared to fetching the revisions from a remote 
location. This is where a cache would be of most use. The revisions are 
local in the cache and it doesn't matter what drive the user branches on 
fetching them from a local drive will nearly always be faster than 
fetching them from a remote location.

Nick