[LAU] Large live recrodings ?

[Kjetil S. Matheussen]

Arnold Krille:
> As the transfer from memory to hd is _the_ slow point of the setup,
> cache-misses or hits don't influence that at all. And when you are not
> calculating anything (apart from 64bit to 32bit double-to-float), you don't
> access the cache. DMA is the keyword. Still it doesn't make saving to disk
> faster than your disks and controllers speed. And I am pretty sure that there
> is _no_ compression involved in that part, otherwise this would seriously
> affect data-integrity if the controller did an unwanted compression.

Okay, but I'm also thinking about the HD cache and the cache between
the OS and the disk. I don't know how it works 
exactly though, but I thought that maybe it didn't write to disk as
often if the cache is constantly filled with zeros.


> Is that enough back-up for my "bombastically spilled out" argumentation?

Sure, much better argumentation.


> A double (or float) to transfer to disk is still a double (float) to transfer
> to disk regardless wether the value is 0, close to zero or something close to
> INFINITY...

Yes, but no doubles or 64 bits are involved in this process, only
32 bit floats.