On 25-Nov-09, at 4:31 PM, Peter Jeremy wrote:
On 2009-Nov-24 14:07:06 -0600, Mike Gerdts <mger...@gmail.com> wrote:
... fill a 128
KB buffer with random data then do bitwise rotations for each
successive use of the buffer. Unless my math is wrong, it should
allow 128 KB of random data to be write 128 GB of data with very
little deduplication or compression. A much larger data set could be
generated with the use of a 128 KB linear feedback shift register...
This strikes me as much harder to use than just filling the buffer
with 8/32/64-bit random numbers
I think Mike's reasoning is that a single bit shift (and propagation)
is cheaper than generating a new random word. After the whole buffer
is shifted, you have a new very-likely-unique block. (This seems like
overkill if you know the dedup unit size in advance.)
--Toby
from a linear congruential generator,
lagged fibonacci generator, mersenne twister or even random(3)
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