Date: Tue, 22 Feb 2000 17:27:46 -0500 From: Doug Ledford <dledford@redhat.com> To: philipp scherer <scherer@venus.t30.physik.tu-muenchen.de> Cc: aic7xxx@freebsd.org Subject: Re: Message-ID: <38B30D62.F93E8081@redhat.com> References: <200002201835.SAA15086@saturn.t30.physik.tu-muenchen.de> <38B047BA.2A66E716@redhat.com> <38B26820.62728363@venus.t30.physik.tu-muenchen.de>
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philipp scherer wrote: > > > This is almost guaranteed to cause problems. First, I'm not sure, but I > > wouldn't be the least bit suprised if termination were always enabled for the > > 50 pin interface, even when set to auto. That would over terminate the bus. > > Second, I wouldn't be suprised if your total cable length exceeds the 1.5m > > maximum cable length. Third, the typical 25 pin connector on the zip drives > > and the zip drive cables interfere with the transmission wave properties of a > > SE SCSI bus, so that can cause additional errors on faster devices (the zip > > drives don't care because they only run in async mode, but they went so cheap > > on construction that you almost can't put a zip drive on the same SCSI bus as > > anything else, which pisses me off, especially if you are anywhere near your > > cable length limits and any other device wants to run in sync mode). > > > > > > You are definitely right. The external cable to the zip was 1m and the > internal > ribbon about 1m with the connection to the scsi controller somewhere in the > middle. Without the external connection the scsi problems disappeared and the > plextor CDROM makes synchronous transfers at 20MB/s. So I will get an > internal ATAPI zip and leave the SCSI zip with my old P90 system where it > makes no problems. But I am still curious about the old driver. Did it work > without problems due to the smaller initial transfer rate ? That and the fact that I fixed some termination bugs that would have helped in your particular case. -- Doug Ledford <dledford@redhat.com> http://people.redhat.com/dledford Please check my web site for aic7xxx updates/answers before e-mailing me about problems To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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