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From: rob@briar.UUCP (Rob Robertson)
Newsgroups: news.software.b
Subject: Re: Proposal: compressing news in the spool directories
Message-ID: <1005@briar.UUCP>
Date: Thu, 16-Apr-87 13:28:10 EST
Article-I.D.: briar.1005
Posted: Thu Apr 16 13:28:10 1987
Date-Received: Sun, 19-Apr-87 10:17:51 EST
References: <536@vixie.UUCP>
Reply-To: rob@briar.philips.Com (Rob Robertson)
Distribution: world
Organization: Philips Laboratories, Briarcliff Manor, NY
Lines: 36
Keywords: proposal, compressed news, storage

There are several drawbacks to keeping news compressed inside the
spool directories.  The two big ones are CPU cycles and that compress
only gives you real gains if what you are trying to compress is
reasonable sized.

On big files, such as source archives, compress will give you about
a 50-60 percent savings in space.  On the average length article
30-40 lines you'll get about a 20-30 percent savings (on just the
article, not the header).  On a one line article with compression
you gain space due to the compression tables.  The point being
that your not going to be gaining the amount of space you might
be expecting.

Now for CPU cycles.  Compress, especially with big articles is
very expensive computationally.  Each time an article is read,
your going to have to invoke compress.  For small articles, this
is not that expensive, but for *.sources.*, your going to notice
it in both user wait time and cpu time.  Also, in batching news
your going to have to uncompress the articles your sending to
another site, and recompress them (you want BIG batches to make
better use of compress, you also want compatiblity with people
who do not do your method of compression).

This posting is not meant to dissuade you, just point out some
design considerations.  There are several situations where you
might want to do this.  If you had severe disk limitations,
alot of unused cpu cycles and/or only a few net readers.

Correct me if I wrong :-).

rob
-- 
       william robertson			philabs!rob@seismo.css.gov
	 (914)  945-6300			philabs!rob.uucp

		"indecision is the key to flexibility"