Path: utzoo!mnetor!tmsoft!torsqnt!news-server.csri.toronto.edu!cs.utexas.edu!uunet!moon!ghost!kianusch
From: kianusch@ghost.UUCP (Kianusch Sayah-Karadji)
Newsgroups: comp.dcom.modems
Subject: Re: How to increase throughput on 9600 bps modem?
Keywords: nn
Message-ID: <19@ghost.UUCP>
Date: 17 Dec 90 10:36:01 GMT
References: <9PF^W}#@ads.com> <17@ghost.UUCP> <1990Dec14.191910.1883@svc.portal.com>
Organization: GHOST (Unigold Remote Site)
Lines: 52

... I write ...
}> ... if you modems have compression mode don't use Zmodem
}> (use Y/X modem instead) ... if you do want to use Zmodem ... turn modem
}> compression of and use only local error correction... same thing with
}> compressed files, (zoo, compress, zip, ...) dont use Zmodem or Modem
}> compression at all.

}	 THIS INFORMATION IS INCORRECT!!  It is true that you do not want
} to send compressed files across a modem on which compression is enabled -
} but the protocol doesn't make a difference, especially ZMODEM.  All of the
} current Macintosh ZMODEM implementations, and most of the PC/UNIX, etc. DO
} NOT support compression!  The ZMODEM spec does provide hooks for RLE
} compression, but Forsberg never recommended implementation due to lack of
} standardization.  His new ZMODEM-90 (Moby-Turbo) provides for a standard
} RLE compression across ZMODEM implemenation, so some newer products may offer
} it as an option, but you will not yet find one on the Mac or UNIX (rzsz).
} And to my knowledge, only dsz on the PC has the ZMODEM-90 extentions.
} 
} + Leonard Rosenthol              | Internet: leonardr@sv.portal.com  +

>Say, enlighten me. What ZMODEM are you using that has compression built into
>ZMODEM? I've yet to see one that does this. Though Forsberg describes the
>potential for comperssion in ZMODEM, he nor anyone else has yet to implement
>it to the best of my knowledge.
>
>   Dave Newman              |  daven@svc.portal.com        |  AppleLink: D0025

... OKAY ... I change my words ... U can use the Zmodem protocoll, but don't
turn it's compression on!

About the INCORRECT INFORMATION, and the enlightment...
Maybe all you guy's should bring your Zmodem programs up to date. :-)
You are ten month behind! It's available at SIMTEL. (sz 3.07 2-02-90)
							     ^^^^^^^
... typing 'sz' with no arguments at my unix prompt gives me ...
---
Send file(s) with ZMODEM/YMODEM/XMODEM Protocol
	(Y) = Option applies to YMODEM only
	(Z) = Option applies to ZMODEM only
Usage:	sz [-2+abdefkLlNnquvwYyZ] [-] file ...
.
.	stuff deleted
.
	Z   Activate ZMODEM compression(Z)
		     ^^^^^^ ^^^^^^^^^^^
sz 3.07 2-02-90 for SYS III/V by Chuck Forsberg, Omen Technology INC
				       ^^^^^^^^
		"The High Reliability Software"
---
-- 
	Kianusch Sayah-Karadji			srhqla!unigold!ghost!kianusch
	 kianusch@ghost.UUCP			pacbell!unicom!ghost!kianusch