Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!tut.cis.ohio-state.edu!morganucodon.cis.ohio-state.edu!paul From: paul@morganucodon.cis.ohio-state.edu (Paul Placeway) Newsgroups: comp.dcom.modems Subject: Re: xyzmodem problems Message-ID: Date: 15 May 89 21:10:37 GMT References: <24404@agate.BERKELEY.EDU> <8457@chinet.chi.il.us> <24440@agate.BERKELEY.EDU> Sender: news@tut.cis.ohio-state.edu Reply-To: paul@cis.ohio-state.edu Distribution: usa Organization: Ohio State Computer Science Lines: 52 In-reply-to: ked@garnet.berkeley.edu's message of 15 May 89 16:08:46 GMT In article <24440@agate.BERKELEY.EDU> ked@garnet.berkeley.edu (Earl H. Kinmonth) writes: In article <8457@chinet.chi.il.us> les@chinet.chi.il.us (Leslie Mikesell) writes: >In article <24404@agate.BERKELEY.EDU> ked@garnet.berkeley.edu (Earl H. Kinmonth) writes: >>machines at UC-Davis and UC-Berkeley. xyzmodem (any of the protocols) >>work for downloads, but uploads INVARIABLY stop after 16 blocks have >>been transferred. This is consistent over half a dozen different machines > >>Any ideas? kermit works (with mark parity). > >Something in the link is set to use XON/XOFF flow control. Packet 17 >in x/ymodem will use a literal 17 (control-S) as the packet number >and hang the link. The only control character kermit uses is >control-A for start-of-packet, others are forced into the printable ... I have had one success. Using rz -e on the host does allow uploads with Zmodem from my ATT 6310 running SCO Xenix. According to the zmodem manual, -e causes the sender (sz) to "quote all control characters." This works on both my leased line and 2400 baud modem. And you have just turned zmodem into something almost as roubust as Kermit (but not quite). I haven't timed zmodem vs kermit on uploads yet. On downloads, at least with base 85 encoded files, kermit seems to win: average xfer rate on 9600 baud line of 560 chars/sec vs 340 for zmodem. Maybe there is more tuning that needs to be done. Interesting. I just did the jrd/pwp cannonocal speed test (transfer ckutio.c), and got 805 c/s between two C-kermits (Sun-3 and MacKermit; both are test versions), using 1016 byte packets and 3 char checksum (CRC). First off, get the test version of C-Kermit from cunixc.cc.columbia.edu; look in the kermit/test directory. (If you do, and you have any problem, make sure to send back a description to info-kermit.) If you have a fairly clean line, set the recieve packet length to about 1000 (1016 is the absolute max, but 1000 is close enough). If you get more than about 3% retrys, drop this to about 500 bytes. If kermit works, use it. (I _could_ be accused of being biased I suppose... :-) ) -- Paul Placeway Mac Kermit coord.