Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!cs.utexas.edu!wuarchive!udel!princeton!phoenix!jwbirdsa
From: jwbirdsa@phoenix.Princeton.EDU (James Webster Birdsall)
Newsgroups: comp.binaries.ibm.pc.d
Subject: Re: Kermit file transfers made easy
Keywords: kermit, scripts
Message-ID: <11474@phoenix.Princeton.EDU>
Date: 12 Nov 89 18:41:45 GMT
References: <1039@chyde.uwasa.fi> <5351@cps3xx.UUCP>
Reply-To: jwbirdsa@phoenix.Princeton.EDU (James Webster Birdsall)
Organization: Princeton University, NJ
Lines: 28

In article <5351@cps3xx.UUCP> hendrick@frith.UUCP (Kenneth J. Hendrickson) writes:
>Kermit uses only 7-bit ascii characters for its file tranfer protocol.
>If you send files with 8-bit characters (binary files like .EXE, .ARC,
>.ZOO, .ZIP, etc.), Kermit uses quoting, where a special character is
>used to flag a byte with the eighth bit set.  If you send binary files
>this way, it effectively doubles the size of the file.

   Correction: Kermit uses the full width of whatever communication line
it has available. On a 7-bit line, it can send text straight and
binaries by quoting (which drops the speed by a lot -- it's usually
faster to uuencode and download as text). On an 8-bit line, it can
send binaries straight. [Your mileage may vary. I'm using MS-Kermit
(in the various versions since 2.29) and C-Kermit (version whatever)
on assorted UNIX boxes.]
   When I did CPS measurements (CPS of the original file, not the
uuencoded version, if appropriate), I found that 8-bit was the fastest
for binaries, followed by 7-bit text of uuencoded file, followed by
7-bit quoted binary. Boosting the packet size to the max of 1000 helped
throughput a lot as well (if you've got dirty lines, this may not be
true -- around here, the lines are very clean and I get maybe one resend
every other month).
   


-- 
James W. Birdsall  jwbirdsa@phoenix.Princeton.EDU  jwbirdsa@pucc.BITNET
   ...allegra!princeton!phoenix!jwbirdsa   Compu$erve: 71261,1731
"For it is the doom of men that they forget." -- Merlin