Path: utzoo!attcan!uunet!husc6!mailrus!cornell!uw-beaver!tektronix!reed!omen!caf
From: caf@omen.UUCP (Chuck Forsberg WA7KGX)
Newsgroups: comp.dcom.modems
Subject: Re: need help with xenix Kermit to PC procomm
Message-ID: <710@omen.UUCP>
Date: 23 Aug 88 09:23:45 GMT
References: <20302@neabbs.UUCP> <11744@oberon.USC.EDU>
Reply-To: caf@omen.UUCP (Chuck Forsberg WA7KGX)
Organization: Omen Technology Inc, Portland Oregon
Lines: 66

In article <11744@oberon.USC.EDU> blarson@skat.usc.edu (Bob Larson) writes:
:In article <20302@neabbs.UUCP> richard@neabbs.UUCP (RICHARD RONTELTAP) writes:
:>I suggest you get the rzsz modules.
:
:This isn't a horrible idea, but you should be warned that XMODEM based
:protocols are sometimes will corrupt the data on a single noise
:character, and are picky about the types of systems and communications
:equipment they run on.

	The main point of the rz/sz programs is to support ZMODEM,
	and ZMODEM does not have any single character failure modes
	`ala XMODEM, YMODEM, Megalink, Telink, WXMODEM, etc.
:
:>Kermit is VERY  slow on binary files and many versions are
:>incompatible. (also the 'super' implementations)
:
:This is just plain wrong as far as I know.  The main "incompatability"
:problem I know of is different default parity.  (Parity is easily
:settable in most implementations, and usually can go into an
:initialization file.)  All versions of kermit are able to transfer
:files to each other.  (Unlike XMODEM, YMODEM, ZMODEM, WXMODEM, etc.)

	Considering all the rewriting I've had to do to the
	C-Kermit routines to get them to work with various Kermit
	implementations, I don't think it's accurate to say
	that all Kermits are compatible.

	I'd like to know which versions of ZMODEM programs are
	unable to transfer files with each other, other than
	those that came out in the first few weeks of ZMODEM's
	initial launching.
	
:A few backward implementations are not able to handle binary files
:over 7-bit communications lines.  (XMODEM has no hope of working at
:all under these circumstances.)  Kermit does have more overhead than
:XMODEM on binary files, about 27% on random binary, less than that on
:most real files.  This does not seem "VERY" slow in comparison to me.
:(ZMODEM or WXMODEM is faster than non-windowing kermit, but windowing
:kermit is faster than XMODEM or YMODEM.)  I have yet to see a

        On BIX accessed via Telenet, the download speeds of 1K XMODEM
        and SuperKermit are about the same; SuperKermit's streaming
        advantage over 1K XMODEM almost makes up for the higher
        overhead.  One may peruse the appropriate "conferences" on BIX
        to read comments about how ZMODEM performs.

:comparison of ZMODEM to windowing kermit from a non-biased source, I
:would expect windowing kermit to be about 5% slower on a typical file
:mixture.

        Rather that attacking other's tests, why not run some tests of
        your own?  Be sure to specify the types of files used and other
        relevant conditions, as is done in the test results shown in
        ZMODEM.DOC (part of YZMODEM.ARC).

:-- 
:Bob Larson	Arpa: Blarson@Ecla.Usc.Edu	blarson@skat.usc.edu
:Uucp: {sdcrdcf,cit-vax}!oberon!skat!blarson
:Prime mailing list:	info-prime-request%ais1@ecla.usc.edu
:			oberon!ais1!info-prime-request

Chuck Forsberg WA7KGX          ...!tektronix!reed!omen!caf 
Author of YMODEM, ZMODEM, Professional-YAM, ZCOMM, and DSZ
  Omen Technology Inc    "The High Reliability Software"
17505-V NW Sauvie IS RD   Portland OR 97231   503-621-3406
TeleGodzilla BBS: 621-3746   CIS: 70007,2304    Genie: CAF