Path: utzoo!utgpu!water!watmath!clyde!att!osu-cis!tut.cis.ohio-state.edu!mailrus!ncar!noao!arizona!naucse!rwi From: rwi@naucse.UUCP (Robert Wier) Newsgroups: comp.sys.mac Subject: Re: MacKermit 0.9(40) problem? Summary: Kermit 1K packets Message-ID: <938@naucse.UUCP> Date: 28 Sep 88 23:03:37 GMT References: <13825@cs.tcd.ie> <10735@coherent.com> Organization: Northern Arizona University, Flagstaff, AZ Lines: 60 Subject: Re: MacKermit 0.9(40) problem? Newsgroups: comp.sys.mac Summary: Kermit extended packet size References: <13825@cs.tcd.ie> <10735@coherent.com> I will second the extended packet size as making a *BIG* difference in the effective speed of Kermit. Going to a 999 byte packet (the maximum allowed on our VAX) nearly doubled the throughput. Still, at 9600 baud, I'm only getting about 425 bytes/sec. I'm not sure where the bottleneck is. I also have used XMODEM (128 byte packets) and it seems to run effectively about 30% faster than Kermit, but unfortunately it doesn't have the nice user interface that Kermit does. For example, I need to be able to wildcard my file specifications but can't do multiple file transfers at once with my version of Xmodem. I also tried Xmodem with 1K packets and found about a 15% increase in speed. The table below summarizes the results of my experiments: File size transferred: 134,561 bytes. Nominal transmission speed (Mac<->Vax) 9600 baud protocol time required effective thruput Xmodem (128 byte packets) 3:30 640 bytes/sec Xmodem (1k byte packets) 3:00 747 bytes/sec Kermit (1k packets) 5:17 424 bytes/sec So, Xmodem with 1k packets is achieving about 80% of the maximum possible speed (assuming no overhead). Kermit is doing a rather dismal 44%. If anyone has other suggestions on speeding up Kermit (or Xmodem - I havn't tried Ymodem or Zmodem) I'd be very interested. - thanks Bob Wier -- College of Engineering & Technology Northern Arizona University NAU Box 15600 Flagstaff, Arizona 86011 {...!att!arizona!naucse!rwi or ...!arizona!naucse!rwi} {IN%"rwi%naucse.UUCP@arizona.EDU"} 602-523-2052 (office) or 602-523-5252 (messages) -----\ -------- \ ----/ ---------------------------- ---- / | for ID picture, | \ ---- Grand Canyon | see Sept. MacWorld, p.141| ---\ / | or Sept. MacUser, p.120| \/ |__________________________| My opinions are completely my own, and not the university's, etc. etc.