meese@vax1.acs.udel.EDU (Tim Meese) (02/09/89)
Has anyone tried to use the ZModem file transfer capability of the recently-posted ZModem 0.7? According to the documentation, once you issue the "sz" command on the Unix end, the Mac is supposed to automatically start receiving the file. Whenever I try to send a file, I see a short burst of characters and my terminal hangs. I would like to fix the file transfer problem because ZModem seems like an otherwise solid product. ( Mainframe-end: VAX-8650 running 4.3 BSD Unix, Mac: SE running System 4.2/Finder 6.0 ). Tim Meese -- Tim Meese | Usenet: meese@vax1.acs.udel.edu Electrical Engineering Department | UUCP: <gateway>!udccvax1!meese University of Delaware | Phone: (302) 738-1658
lauac@wheeler.qal.berkeley.edu (Alexander Lau) (02/09/89)
In article <2803@udccvax1.acs.udel.EDU> meese@vax1.acs.udel.EDU (Tim Meese) writes: >Has anyone tried to use the ZModem file transfer capability of the >recently-posted ZModem 0.7? According to the documentation, once >you issue the "sz" command on the Unix end, the Mac is supposed to >automatically start receiving the file. Whenever I try to send a >file, I see a short burst of characters and my terminal hangs. I >would like to fix the file transfer problem because ZModem seems >like an otherwise solid product. ( Mainframe-end: VAX-8650 running >4.3 BSD Unix, Mac: SE running System 4.2/Finder 6.0 ). > > Tim Meese > Ditto for me, too...I'm using sz/rz on a Sun 3/50 running Sun UNIX 4.2, Release 3.5, Zmodem 0.7 on a Mac SE running System 6.0.2 and Finder 6.1, with various inits... However, the auto-receive works fine from an Opus BBS, so I think it might have something to do with the Sun 3/50 end rather than the Mac end... Sending from Zterm to UNIX causes a hang as well, I haven't tested it on anything else yet... --- Alex {ihnp4,backbones}!ucbvax!qal.berkeley.edu!lauac
dplatt@coherent.com (Dave Platt) (02/09/89)
In article <20127@agate.BERKELEY.EDU> Alexander Lau writes: > In article <2803@udccvax1.acs.udel.EDU> Tim Meese writes: > >Has anyone tried to use the ZModem file transfer capability of the > >recently-posted ZModem 0.7? According to the documentation, once > >you issue the "sz" command on the Unix end, the Mac is supposed to > >automatically start receiving the file. Whenever I try to send a > >file, I see a short burst of characters and my terminal hangs. I > >would like to fix the file transfer problem because ZModem seems > >like an otherwise solid product. ( Mainframe-end: VAX-8650 running > >4.3 BSD Unix, Mac: SE running System 4.2/Finder 6.0 ). > > Ditto for me, too...I'm using sz/rz on a Sun 3/50 running > Sun UNIX 4.2, Release 3.5, Zmodem 0.7 on a Mac SE running > System 6.0.2 and Finder 6.1, with various inits... > > However, the auto-receive works fine from an Opus BBS, so > I think it might have something to do with the Sun 3/50 > end rather than the Mac end... I've been able to use ZTerm for both uploading and downloading to my Sun network (dialin lines feeding a 3/280, then rlogin to my 3/60 workstation). There are a couple of tricks, though. Issue #1: data bits and parity. The ZMODEM protocol _requires_ the presence of an 8-bit data path from the sender to the receiver (although not necessarily in the other direction). Sun systems seem to want to send 7-bits-plus-parity during normal operations. If you set ZTerm to "8 data bits, no parity", then you tend to see garbage when you dial up your Sun (because ZTerm is "seeing" the parity bit on some characters and is being fooled into switching to the Big Blue extended character set. The obvious way to keep ZTerm from printing nonsense is to tell it to use 7 bits, 1 parity bit (I forget whether it wants odd or even). DO NOT DO THIS! If you do, ZTerm will be unable to send or receive 8-bit data during file transfers, and ZMODEM downloads will not work! [ZTerm should, arguably, switch over to 8/0 during transfers and then back to 7/odd or 7/even when the transfer is done. It doesn't, though.] So... when configuring ZTerm to talk to a Sun, instruct it to use 8 data bits, no parity, and to inhibit the use of the extended character set. This will work just fine. Issue #2: data overruns during downloads. If you are using "sz" via a network-based remote-login connection, or are hooked up to your Sun via a high-speed serial connection, you may find that sz tends to over-run the Mac's ability to receive and swallow ZMODEM data. The result will usually be timeouts, errors, loss of synchronization, and (in general) a very difficult time doing downloads. Solution: use the "-w" option to put sz into a windowed mode. This option isn't in the man page, but is displayed if you invoke sz with a bad option. Suggested command: sz -w 2048 file1 file2 .... This will cause sz and ZTerm to negotiate a sliding-window buffer of 2048 bytes. sz will send 512-byte packets, with a "please acknowledge" attached to the end of each one; if ZTerm gets bogged down, sz will pause when the window is exhausted (4 packets) and will start sending again when it receives the ackowledgement for the first packet in the window. If ZTerm is able to keep up with your host, then sz will be transmitting continually, and your line utilization will run up around 95%. Issue #3: overruns during uploading. It's possible for ZTerm to over-run your Sun during an upload. Unfortunately, ZTerm does not yet support the ZMODEM sliding-window option. The only way to keep ZTerm from flooding your host at high line speeds is to use software (XON/XOFF) flow control, so that your host XOFFs when its input buffers begin to bulge, and XONs again when the buffers have been drained. Hope this all helps! -- Dave Platt FIDONET: Dave Platt on 1:204/444 VOICE: (415) 493-8805 UUCP: ...!{ames,sun,uunet}!coherent!dplatt DOMAIN: dplatt@coherent.com INTERNET: coherent!dplatt@ames.arpa, ...@sun.com, ...@uunet.uu.net USNAIL: Coherent Thought Inc. 3350 West Bayshore #205 Palo Alto CA 94303
jac@petsd.UUCP (Jim Clausing) (02/09/89)
In article <20127@agate.BERKELEY.EDU> lauac@wheeler.qal.berkeley.edu.UUCP writes: <In article <2803@udccvax1.acs.udel.EDU> meese@vax1.acs.udel.EDU (Tim Meese) writes: [...stuff about sz not working from Unix to Zmodem...] <> <> Tim Meese <> < <Ditto for me, too...I'm using sz/rz on a Sun 3/50 running <Sun UNIX 4.2, Release 3.5, Zmodem 0.7 on a Mac SE running <System 6.0.2 and Finder 6.1, with various inits... < <However, the auto-receive works fine from an Opus BBS, so <I think it might have something to do with the Sun 3/50 <end rather than the Mac end... < <Sending from Zterm to UNIX causes a hang as well, I haven't <tested it on anything else yet... Receiving was a problem for me (so this isn't restricted to Sun 3/50s), I ended up switching over to YMODEM for downloading, but uploading worked just fine. Make sure for uploading to Unix that you change the Zmodem parameters (I don't remember the actual menu item name) to have the program send an 'rz' to the Unix machine rather than a 'uz'. < <--- Alex -- Jim Clausing Voice: (201)758-7693 Parallel Processing Tools Grp. CI$: 74726,2015 GEnie: J.CLAUSING Concurrent Computer Corp. Internet: jac@petsd.ccur.com Tinton Falls, NJ 07724 UUCP: {att, rutgers, princeton}!petsd!jac