Xref: utzoo comp.dcom.modems:8561 comp.mail.uucp:5963
Path: utzoo!mnetor!tmsoft!torsqnt!hybrid!scifi!bywater!uunet!cbmvax!grr
From: grr@cbmvax.commodore.com (George Robbins)
Newsgroups: comp.dcom.modems,comp.mail.uucp
Subject: Re: News compression and T2500's
Message-ID: <19462@cbmvax.commodore.com>
Date: 4 Mar 91 01:44:05 GMT
References: <1991Mar3.213145.6760@shaman.com>
Reply-To: grr@cbmvax.commodore.com (George Robbins)
Organization: Commodore, West Chester, PA
Lines: 24

In article <1991Mar3.213145.6760@shaman.com> jiro@shaman.com (Jiro Nakamura) writes:
> Folks -
>    I was wondering about CNews compression formats and what was the most
> efficient way to transport news. If my memory serves me correctly, Cnews
> using compress (1) to compress the news batches, and compress uses a 
> Lempel-Ziv compression format.
>    Now..... I was wondering if it might be more efficient to *not* pre-compress
> the news at the *system* level, but let the modem do the compressing itself.

It's been previousy asserted that the number of instructions executed
per-byte in the compress program is significantly less than that involved
in typical unix character I/O processing.  If so, then minimizing the
number of characters at the rs232 interface is still an overall win.

There is also a question as to whether compression in a modem can be as
effective, since the modem (typically) has more limited memory resources
and must compress "on the fly".  Obviously, the real compression efficiency
depends on the quality of the algorithm and how well the data matches it's
assumptions.

-- 
George Robbins - now working for,     uucp:   {uunet|pyramid|rutgers}!cbmvax!grr
but no way officially representing:   domain: grr@cbmvax.commodore.com
Commodore, Engineering Department     phone:  215-431-9349 (only by moonlite)