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Newsgroups: comp.unix.bsd Path: sserve!manuel!munnari.oz.au!uniwa!cujo!marsh!cproto From: cproto@marsh.cs.curtin.edu.au (Computer Protocol) Subject: COM driver and X11 Message-ID: <cproto.710554678@marsh> Summary: COM driver looses characters (silo overflow) Keywords: COM X11 Sender: news@cujo.curtin.edu.au (News Manager) Organization: Curtin University of Technology Date: Wed, 8 Jul 1992 00:17:58 GMT I'm running 386BSD (17/03/92) and experience silo overflows when running a kermit filetransfer (2400 b/s) in background and anything (even just a ls) in foreground. I get the silo overflows both with the released com driver as well as with the latest post which is supposedly fixing this problem. My COM port is implemented with a NS16450 so I can't use the 16 byte FIFO supported in the latest driver. But even with a NS16550 with the FIFO I doubt whether the driver would keep up due to the TTY stuff it has to go through for every received character (at 9600 b/s or higher). BTW I also experience the problem running X and moving the serial mouse while just launching some X application. I have a fast machine but not too much memory: 486DX / 33 Mhz 4 Mbyte memory 64 Kbyte secondary cache 210 Mbyte IDE HD I think the driver should be really split into two parts. A lower level driver which is handling the receive interrupts at a high priority and a very short execution path. This part should write received characters plus status into a circular buffer and then cause some software interrupt to invoke the higher level driver to do all the fancy TTY bits. Before I start on this please let me know what you guys think ?!? Regards - Tibor Sashegyi (cproto@abel.cs.curtin.edu.au)