> This is a terrible assumption in general (i.e. if filesize % blocksize 
quoted text
> is close to uniformly distributed).  If you remove one byte and the data 
> is stored with blocksize B, then you either save zero bytes with 
> probability 1-1/B or you save B bytes with probability 1/B.  The 
> expected number of bytes saved is B*1/B=1.  Since expectation is linear, 
> if you remove x bytes, the expected number of bytes saved is x (even if 
> there is more than one byte removed per file).

You didn't calculate the probability of actually saving a full block 
or not (that's the only thing that matters). I assumed it's relatively
small and can be ignored in practice since the amount of end white
space is negligible compared to total file size.

-Andi
-
unsubscribe notice
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/