gillies@p.cs.uiuc.edu (05/31/90)
I occasionally would like to upload 100k postscript files to another machine at the maximum possible throughput. Currently, I have tried using zterm 0.85 at 38400 baud. It runs fine for about 10k, then the zmodem gets stuck, and often it wedges permanently. My mac is connected as follows: Mac SE/030 ---RS232---> Encore Annex ---Ethernet---> Multimax Box(68020?) (or pyramid) I am uploading through an encore annex box, which concentrates the data using either (1) multimax call, (2) unix rlogin, or (3) telnet protocol. Since the ethernet should not be a bottleneck at these slow speeds (3.2k/sec), I assume that the host is dropping packets, or the mac is dropping responses, and someone is not timing out correctly (because the Mac just hangs). What can I do to improve the situation? I have some questions (1) will white knight 11.0 run zmodem at 38400, perhaps under scripting control? Does it work as nicely as zterm 0.85? (2) is there a later version of zterm 0.85? (3) is there something wrong with my UNIX zmodem program? I know it has bugs, because in the past uploads have terminated with the UNIX host being short about 2Kbytes out of 100K, needless to say, the upload was worthless. (4) is there something I can do to the terminal concentrator, to xon-xoff, or elsewhere to reduce the rate of packet/ack dropping, or to get UNIX/zterm 0.85 to restart more quickly after a transmission error? Thanks, Don W. Gillies, Dept. of Computer Science, University of Illinois 1304 W. Springfield, Urbana, Ill 61801 ARPA: gillies@cs.uiuc.edu UUCP: {uunet,harvard}!uiucdcs!gillies
RP1VOPER@MIAMIU.BITNET (Rob Pickering) (06/02/90)
White Knight should be able to handle speeds up to 56 kbaud. And yes, the z-modem in White Knight is very nice. However, you need to upgrade from 11.x to 11.7 (the newest I believe.). there were some early problems with z-modem that Scott Watson fixed the patches are on America Online and I'll post them to mac.binaries soon. -Rob