Date: Tue, 22 Feb 2000 11:42:40 +0100 From: philipp scherer <scherer@venus.t30.physik.tu-muenchen.de> To: Doug Ledford <dledford@redhat.com>, aic7xxx@freebsd.org Subject: Re: Message-ID: <38B26820.62728363@venus.t30.physik.tu-muenchen.de> References: <200002201835.SAA15086@saturn.t30.physik.tu-muenchen.de> <38B047BA.2A66E716@redhat.com>
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> 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 ? Thank you for your help Philipp To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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