Proposal for solving CD Size problems

[Christian Leber]

On Tue, Sep 26, 2006 at 04:19:37PM -0500, Steven Harms wrote:

ToFu removed

>    Since this discussion is all about people without dvd drives, at what
>    point do we assume they have enough processing power to decompress the
>    image hundreds of times per session?

Assume?
It looks like there is either no desktop CD at all or a reduced one.
A CD with lzma compression could be an alternative that is a little bit
slower.

>    I mean if they don't have a dvd
>    drive, then they probably have < 256MB of ram, so when things are swapped
>    in and out of ram massive decompressing will occur, and again the same
>    goes with their processing power.

First I don't get what paging has to do with the decompression, other
than that there is less cache. (afair no decompressed data is cached
anyway)
Second when you have an ultra slow system with < 256 MB of ram you are used
to wait forever anyway, so you can also wait a little bit longer for the
few occasions you are using the live CD.

well, some numbers:
-rw-r--r--  1 ijuz ijuz 306032640 2006-09-27 00:42 usr_bin.tar  (the /usr/bin from my dapper box)
-rw-r--r--  1 ijuz ijuz 117850036 2006-09-27 00:44 usr_bin.tar.gz
-rw-r--r--  1 ijuz ijuz  74668054 2006-09-27 00:50 usr_bin.tar.lzma

compression took with 2 Ghz 84 sec for gzip and 426 sec for lzma.

I tested decompression on the slowest system i have easily access too, a
PII/350:
lzma decompression of said file: 82 sec -> 3.73 MB/s
gzip decompression 27 sec -> 11.33 MB/s

(on my 2 Ghz box it takes 14 sec, so it can decompress faster than a CD
drive could read the compressed data)

Oh, i also have numbers from the Knoppix in my last mail, unfortunally i
don't remember if my testbox back than was a 750 or a 1533 mhz athlon.

Anyway, booting took 94 sec with gzip compression and 102 sec with lzma.
(this proper ordering of the files on the CD - the unmodified cloop
knoppix took 99 sec)

When you really care about performance... have the files that are used
on every boot loaded in a burst from a gzip compressed part of the CD,
seeking is the real timeeater.


Christian Leber

-- 
http://rettetdieti.vde-uni-mannheim.de/