using bzip2 to compress man-pages
Mikhail Teterin
mi+mx at aldan.algebra.com
Thu Sep 22 13:53:28 PDT 2005
Ulrich Spoerlein wrote:
> 1. I dont want to wait for my manpages to display, they have to be on
> screen instantanously.
A human being can not distinguish between a millisecond and a microsecond. The
difference between gzcat and bzcat is far less dramatic.
The space-saving potential can substantial, however -- see below. Being able
to stick us useful root filesystem (with /usr) onto a USB key can be useful
for some applications.
It just makes sense -- and the CPUs are advancing faster than storage devices.
Charles Swiger wrote:
> My guess is that roughly 95% of the manpages aren't going to save a
> disk sector by switching.
One does not need to save the entire sector-size. Only the (size %
sector_size), which currently pushes the file into an additional sector.
The following command line assumes, the sector size of 512 bytes and the bzip2
vs. gzip saving of only 10%. Notice, it takes care to look once at every
manual page even if it is has more than one alias (eliminating pages with the
same inode). Try this on your system:
% find /usr/share/man/ -name \*.gz -ls | sort -k 1 | awk '$1 == inode { next }
{ inode=$1; total++; if ($7 % 512 < $7*0.10) savings++ } END {print savings "
out of " total}'
1200 out of 2694
1200 files out 2694... That's a little more than 5%...
The other advantage is the stride towards freer-licensed software.
-mi
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