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Path: sserve!manuel!munnari.oz.au!uunet!spool.mu.edu!sdd.hp.com!wupost!uwm.edu!rutgers!igor.rutgers.edu!athos.rutgers.edu!hedrick From: hedrick@athos.rutgers.edu (Charles Hedrick) Newsgroups: comp.unix.bsd Subject: more about 386BSD SLIP Message-ID: <Sep.7.14.41.53.1992.602@athos.rutgers.edu> Date: 7 Sep 92 18:41:54 GMT Organization: Rutgers Univ., New Brunswick, N.J. Lines: 12 Aside from the well-known silo overflow problem, I think there's another problem in the serial driver. I just had output hang in SLIP. There's a well-known problem that causes output interrupts not to happen sometimes. I've heard people who really know the serial devices claim that with correct interrupt handling code this won't happen, but in every piece of device-level code I've seen, it has. The problem showed up in SLIP8250 (the MSDOS packet driver -- I have a fixed version), in the FTP Inc SLIP implementation (they fixed it a couple of years ago), and Linux (until it was fixed several releases ago). The obvious solution is to time out serial writes. If you send a character and don't get output done within a reasonable time, just assume the output worked and go ahead with the next.