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xz (was Re: Mac-only binary, was Re: Modernizing a Macintosh LC III)



Finn Thain dixit:

>I don't know how much memory is needed by the "xz -0d" algorithm. The xz 

RTFM ;-)

                     Preset   DictSize   CompCPU   CompMem   DecMem
                       -0     256 KiB       0        3 MiB    1 MiB
                       -1       1 MiB       1        9 MiB    2 MiB
                       -2       2 MiB       2       17 MiB    3 MiB
                       -3       4 MiB       3       32 MiB    5 MiB
                       -4       4 MiB       4       48 MiB    5 MiB
                       -5       8 MiB       5       94 MiB    9 MiB
                       -6       8 MiB       6       94 MiB    9 MiB
                       -7      16 MiB       6      186 MiB   17 MiB
                       -8      32 MiB       6      370 MiB   33 MiB
                       -9      64 MiB       6      674 MiB   65 MiB

It depends on what it was _compressed_ with.

Rule of thumb: xz -0 is faster than gzip -6 in compression and
has about the same ratio, xz -2 compresses about as fast as gzip -6
with better ratio; decompression times are decent (given enough RAM)
and xz always beats bzip2 considering bzip2 decompresses… badly.

With -e, compression ratio increases at no decompression cost
(neither RAM nor speed), only compression cost (speed, not RAM,
but quite a lot of speed).

bye,
//mirabilos
-- 
„Also irgendwie hast du IMMER recht. Hier zuckelte gerade ein Triebwagen mit
der Aufschrift "Ostdeutsche Eisenbahn" durch Wuppertal. Ich glaubs machmal
nicht…“						-- Natureshadow, per SMS
„Hilf mir mal grad beim Denken“			-- Natureshadow, IRL, 2x


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