Unnecessary tar-compress-uuencodes

[David H. Brierley]

In article <sean.647630062 at s.ms.uky.edu> sean at ms.uky.edu (Sean Casey) writes:
>Compressing an article reduces phone time. If compress finds a file
>is bigger after compression, it doesn't compress it. So the phone
>costs really aren't increased by users doing their own compression.

Almost, but not quite.  If you run the compress program by typing
"compress filename" and the resulting compressed file is bigger than
the original then compress will save the original and delete the 
compressed file.  On the other hand, if you type "compress <f1 >f2"
then the compress program will happily create an output file which
is larger than the input file.  Since news uses the compress program
in a pipeline, this is essentially what happens.  Here is an example:

	-rw-rw----  1 dave    family    73150 May 23 17:32 spool.sum
	compress <spool.sum >test1.Z
	-rw-rw----  1 dave    family    15791 Jul 11 09:40 test1.Z
	compress <test1.Z >test2.Z
	-rw-rw----  1 dave    family    23099 Jul 11 09:41 test2.Z

As you can see, test2.Z is 46% larger than test1.Z.  This was done using
full 16bit compression.  If you use 12bit compression, which a lot of sites
are using, the results are even worse.
-- 
David H. Brierley
Home: dave at galaxia.Newport.RI.US    {rayssd,xanth,att} !galaxia!dave
Work: dhb at quahog.ssd.ray.com        {uunet,sun,att,uiucdcs} !rayssd!dhb