In message , Paul
writes:
J. P. Gilliver (John) wrote:
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I'm not understanding what you mean by "erase" here. Are SSDs different
in some way, i. e. aren't bits erased anyway when overwritten?

Having read further - the answer to my question is yes. Writing can only
be done to erased blocks, unlike in a conventional drive; thus when
files are erased (or rewritten, meaning the old data is erased), in an
SSD the controller has to go around afterwards actually erasing - it's
not just a matter of modifying the directory file. (Directory files
themselves have to be treated in this manner too.)
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The drive works most efficiently, if you need to write block-sized
things. Writing "small things", smaller than the block size, leads
to "write amplification". Write amplification refers to needing to

I suppose we're stuck with it now, but whoever invented that phrase
should be ...

erase and rewrite major portions of a block. This article has some
nice pictures, showing how the SSD controller works behind the
scenes, to get the best usage from the flash.

http://en.wikipedia.org/wiki/Write_amplification
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--
J. P. Gilliver. UMRA: 1960/1985 MB++G.5AL-IS-P--Ch++(p)Ar@T0H+Sh0!:`)DNAf

"He hasn't one redeeming vice." - Oscar Wilde