davidm@nixtor.UUCP (David Macklem) (06/10/89)
This question is probably asked everytime a Pyramid site hooks up a Telebit Trailblazer but, anyways, here goes. I have a Nixdorf Targon 35 running TOS3.3 (I don't know the corresponding Pyramid version number but the att side is SVR2 not SVR3 and the uucp is not HDB). When I first hooked up Telebit TB+ modems to my Pyramid, transfers over these modems via uucico at 9600 baud caused disturbing messages on the console: "itp41: port0 uart overrun". (ipt41, port 0 was the port being used by the uucico process). Eventually the uucico process would die. I was able to fix this (for most transfers) by setting ITPHOWOFTEN=2 in the kernel and re-making it. (No, I don't have source). This has solved the problem for our mail and news feed. However, currently, one of our uucp neighbours is trying to send large files (>1meg) to our machine and these annoying messages are re-appearing. This time the screwed up uucico process sometimes crashes the Pyramid. If the system does not crash but the uucico process dies, further uucico transfers to/from other sites (which would use the same itp if not necessarily the same port) exhibit the same behaviour. The machine has to be powered down and back up again to get it back to a normal state. (Our users like this :-)). It's almost as if the uart overruns are screwing up the itp so badly that it can't recover. As far as I can tell, the modem registers (at both ends) are set properly (hardware flow control only, g-protocol spoofing, 8bits, no parity, etc..) and as mentioned, we don't have any trouble with our full news feed or mail. Admittedly, the news batches come in files that are <= 50k but there is still a total of about 3meg per day. I have told this offending neighbour not to transfer files > 100k but I'm hoping there is a better solution. Has anyone out there seen this before and, more importantly, did you fix it? If so, how? I'm grateful for any help. -- David Macklem Nixdorf Computer Canada, Limited davidm@nixtor uunet!jtsv16!geac!nixtor!davidm
csg@pyramid.pyramid.com (Carl S. Gutekunst) (06/11/89)
In article <337@nixtor.UUCP> davidm@nixtor.UUCP (David Macklem) writes: >I have a Nixdorf Targon 35 running TOS3.3 (I don't know the corresponding >Pyramid version number but the att side is SVR2 not SVR3 and the uucp is not >HDB).... When I first hooked up Telebit TB+ modems to my Pyramid, transfers >over these modems via uucico at 9600 baud caused disturbing messages on the >console: "itp41: port0 uart overrun". Egads. You're on OSx 3.1. You are seeing a bug in the ITP microcode that was fixed here in August 1986. You can reduce ITPHOWOFTEN, although that can be self-defeating since doing so hurts overall system throughput. The real solu- tion is to work through the proper Nixdorf channels and get the current ITP microcode. I don't know if there are any compatability issues involved, or if Nixdorf has modified the microcode from Pyramid's version. Something else that will help is using RTS/CTS hardware flow control. You should be doing that anyway, since the TrailBlazer has problems if you leave its XON/XOFF flow-control enabled when UUCP transfers are done. (Everyone at Telebit keeps telling me that the TrailBlazer automatically turns of XON/XOFF when the modem goes into "uucp spoof" mode. My experience says that's not the case.) <csg>