[ILUG] A sysadmin dream come true !
jos at dublin.com
Mon Jan 14 12:32:05 GMT 2002
That's nothing - look at lzip (lossy zip):
Reduces all files down to 10% or even 0% of their original size!
From the FAQ:
It utilizes a two-pass bit-sieve to first remove all unimportant data
from the data set. Lzip implements this quiet effectively by eliminating all
of the 0's. It then sorts the remaining bits into increasing order, and
begins searching for patterns. The number of passes in this search is set to
(10-N) in lzip, where N is the numeric command-line argument we've been
telling you about.
For every pattern of length (10/N) found in the data set, the algorithm
makes a mark in its hash table. By keeping the hash table small, we can
reduce memory overhead. Lzip uses a two-entry hash table. Then data in this
table is then plotted in three dimensions, and a discrete cosine transform
transforms it into frequency and amplitude data. This data is filtered for
sounds that are beyond the range of the human ear, and the result is
transformed back (via an indiscrete cosine) into the hash table, in random
Take each pattern in the original data set, XOR it with the log of it's
entry in the new hash table, then shuffle each byte two positions to the left
and you're done!
And you can see, there is some very advanced thinking going on here. It
is no wonder this algorithm took so long to develop!
> On Mon, 14 Jan 2002, Stephane Dudzinski wrote:
> Wow! Infinite compressions and backups on a floppy, what a great new
> company !
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