shredding files on a flash drive

[Anthony de Boer]

Lennart Sorensen wrote:
> Besides does anyone actually bother wasting time on compressed
> filesystems anymore?

I've wasted CPU time on worse things.  :-)

That said, compressed filesystems would tend to be more desirable for
flash devices, since they tend to lag a lot behind other devices in size
and be more expensive per size.  Also, when used to cart files from one
computer to another, there's less need for random access within files;
you're not likely to mount a MySQL database there.

Back when flash was far more expensive than RAM, I built a system that
extracted a RAM filesystem from a gzipped tarball on flash, and we
deployed several of those across Canada.  For similar use you now have
squashfs (and the earlier cramfs).  If you're dealing with raw flash,
there's JFFS2, but it's less applicable with USB devices and the like
that we access at a higher level already.

There's also the consideration that gzipped tarballs and most popular
multimedia file formats incorporate compression internally, so you're
not gaining anything from another layer of compression if carting files
like that around is your application.

Compression of a read-write filesystem is something that I recall people
were doing in the DOS era (Wikipedia tells me "Stacker" and "Doublespace"
were the names, and I'm recalling a lawsuit in there too), but at least
in the Linux mainstream the idea never really caught on.

So yes, squashfs is current technology.

-- 
Anthony de Boer
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