Path: utzoo!attcan!uunet!husc6!panda!teddy!jpn
From: jpn@teddy.UUCP (John P. Nelson)
Newsgroups: comp.sources.d
Subject: Re: Standard for file transmission
Message-ID: <4813@teddy.UUCP>
Date: 24 May 88 14:28:11 GMT
References: <292@cullsj.UUCP> <696@fig.bbn.com> <2932@cognos.UUCP> <3055@encore.UUCP> <4776@teddy.UUCP> <7810@ncoast.UUCP>
Reply-To: jpn@teddy.UUCP (John P. Nelson)
Organization: GenRad, Inc., Concord, Mass.
Lines: 42

>| Most binary files that are compressed, uuencoded, then compressed again
>| are SMALLER than binary files that are simply uuencoded, then
>| compressed.  I have yet to see anyone post results that refute this.
>
>Single files, yes.  But the quoted message above specifically says BATCHES.
>...
>to verify whether batch compression is reduced, we have to modify sendbatch...

Well, anyone is welcome to MAKE this expermiment, but it is totally
unnecessary in my opinion.

Of COURSE pre-compressing is going to reduce the compression ratio
of a batch.  This is irrelevent, because less data needs to be batched.

Remember:  "compress" uses an ADAPTIVE Lempel-Ziv method:  If the old
string table isn't working, Compress will RESET the table and start
over, right in the middle of the file being compressed.  Neither a
uuencoded file nor a compressed uuencoded file will look much like an
ordinary ascii file: the string table used in either "uuencode" case
will not look much like the string table generated for normal text
batches.  Either type of "uuencode" will cause "compress" to reset the
string table.

Besides, I think we have gotten off the track here.  Even if
pre-compressing DOES adversely affect the overall size of data
transmitted slightly:  I think we have shown that it doesn't increase
the size of the data SIGNIFICANTLY:  in the simplest case, it REDUCES
the size.  The most common use of pre-compressing is the use of "ARC"
(or "zoo") to bundle multiple files together:  There is no other way
convenient way to "bundle" binary files at the moment.  I think we have
shown that the use of ARC to build bundles of binary files is NOT
detrimental!  I think we should now focus our collective energies on a
more productive topic.

The real unresolved issue, of course, is whether to allow binaries on
USENET at all.

-- 
     john nelson

UUCP:	{decvax,mit-eddie}!genrad!teddy!jpn
smail:	jpn@genrad.com