you're not going to believe this.

David Kelly dkelly at
Tue Jun 23 20:14:36 UTC 2009

On Tue, Jun 23, 2009 at 09:46:01PM +0200, Wojciech Puchar wrote:
> >>and lifetime.
> >
> >Even a flash filesystem will have to do wear levelling.
> yes - but it don't have to copy blocks that are free. with disk
> emulation - it doesn't know anything about filesystem and don't know
> what blocks are free.

If it is swapping from heavily used blocks to lightly used blocks then
"so what" if there is an "unnecessary" read/write? Perhaps its harder to
determine if unused than to simply move the data. I seem to recall
something like this in comments in the FreeBSD virtual memory manager in

Don't want to leave the old data laying around for security reasons so
even if the blocks are unused the formerly heavily used blocks need to
be scrubbed.

As I originally said to Gary Kline, "Don't let someone scare you away
from the 99.8% solution waiting on the 99.9% solution."

David Kelly N4HHE, dkelly at
Whom computers would destroy, they must first drive mad.

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