Path: utzoo!attcan!uunet!mitel!sce!cognos!sysint!robert From: robert@sysint.UUCP (Robert Nelson) Newsgroups: comp.windows.ms Subject: Re: Communication Error CE_OVERRUN under Windows Message-ID: <250@sysint.UUCP> Date: 9 Aug 89 03:28:44 GMT References: <6755@cognos.UUCP> Organization: Systems Interface Inc, Ottawa, Ontario, Canada Lines: 58 chrisr@cognos.UUCP (Christine Roine) writes: >Communication Problem >--------------------- >One of our applications accesses and displays information retrieved >from a host computer via a serial communication line. We have a >communications bug that occurs fairly reliable, but cannot be >reproduced with the same sequence of steps every time. (Programmer's >nightmare!) The application runs perfectly for as much as 10 - 15 >minutes. Then, suddenly, we get a CE_OVERRUN error returned by >GetCommError(). The documentation explains this as "A character >is not read from the hardware before the next character arrives. >The character is lost." Our communication software asks for a >retransmission of the data that was lost, but CE_OVERRUNs keep >occurring in the retransmitted data. >At first we thought that perhaps we were writing over the interrupt vectors >in low memory. However, a closer look at the data we were receiving >revealed that we get some correct data after a CE_OVERRUN occurs. >In some cases, for example, we are just dropping a couple of characters >in the middle of a message. [ Other descriptions of supposed causes and attempted solutions removed ... ] >Has anyone run into this or a similar problem? I believe that interrupts being disabled too long is your problem. I don't think that disk interrupts are the cause unless one or more of the following are true: 1) your system is really slow (Nobody would use Windows on an XT :-) Would they?? 2) you have a disk cache program which disables interrupts while transfering whole tracks 3) your disk controller is really slow 4) your disk sector interleave is wrong. I have seen problems with the windows asynch driver when used with EMS drivers. If you are using one, try running windows with the /n option and if that doesn't help try disabling the EMS driver in your config.sys file. If the problem is with the EMS driver check with the vendor for a later version or a fix. >-- >Christine Roine Cognos Incorporated S-mail: P.O. Box 9707 >Voice: (613) 738-1440 x6111 3755 Riverside Drive > FAX: (613) 738-0002 Ottawa, Ontario > UUCP: decvax!utzoo!dciem!nrcaer!cognos!chrisr CANADA K1G 3Z4 -- Robert B. Nelson Systems Interface Inc. Phone: (613) 727-5001 223 Colonnade Road South UUCP: uunet!mitel!sce!cognos!sysint!robert Nepean, Ontario, CANADA, K2E 7K3