Date: Thu, 26 Oct 1995 12:09:50 +1000 (EST) From: raoul@cssc-syd.tansu.com.au (Raoul Golan) To: freebsd-questions@freebsd.org Subject: Too many UUCP checksum errors! Help! Message-ID: <199510260209.MAA03703@kiwi.ind.tansu.com.au>
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Guys (& gals), I've written about this before, but now I have a little more info. I thought the noisy line was to blame, but it's not as simple as that. It's not really a serious problem anymore, but something that I'm curious about. This is my situation. I'm using 2.0.5-RELEASE, and I'm getting lots of checksum errors on UUCP over my 16550A UART, mostly due to lost bytes. I swap cards to a 16450 UART, and the problem disappears. I tried using the 16550A UART again, this time with the FIFO disabled in the kernel, but the checksum errors were still there. I have a noisy line, so I always enable the modem's error correction. I don't get a single checksum error over the 16450, but lots of lost bytes over the 16550A. I have enabled crtscts, and disabled xon/xoff. I must be doing this OK, since I get no problems over the 16450. Also, I used to run Linux UUCP over the same line. No problems there, even with the 16550A. One more thing: the 16550A is on a VESA slot, wheras my 16450 is on an ISA slot. I have a DX4-100, i.e. my clock speed is 33, so I don't really expect the bus speed to be causing any problems (especially since Linux works at the same speed). I usually connect at 14.4K, but the situation is the same regardless of the modem speed I connect at. Funny thing is that I can run Netscape quite happily over the same UART without any problems - perhaps SLIP handles lost bytes better than the UUCP protocols? (BTW, I don't run UUCP over tcpip, but through direct dialup) Also, I get nothing about serial problems in /var/log/messages. It's no big deal for me to use a 16450, just to get FreeBSD UUCP to run. It sounds like the 16550A driver could be dropping bytes, but I'm not sure. I'm just interested in what could be going wrong. I was hoping that this additional information may give someone a hint as to what's happening. Thanks to you all, Raoul
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