Date: Thu, 25 Feb 1999 22:46:42 +0100 (CET) From: Metod Kozelj <metod.kozelj@rzs-hm.si> To: Doug Ledford <dledford@redhat.com> Cc: Metod Kozelj <metod.kozelj@rzs-hm.si>, Tom Browder <tom2@fwb.asi.srs.com>, AIC7XXX Mail List <aic7xxx@FreeBSD.ORG> Subject: Re: Linux Alpha and Adaptec 2940 Message-ID: <Pine.HPP.3.96.990225223327.9858E-100000@hmljhp.rzs-hm.si> In-Reply-To: <36D570DB.3C809B7@redhat.com>
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Hello, On Thu, 25 Feb 1999, Doug Ledford wrote: > > I've had problems with similar setup you have. The external SCSI-2 DAT > > would just hang my box. After some testing I found out, that if I hook the > > DAT to internal 50-pin connector, it works, otherwise it doesn't. > The external connector on a 2940UW is a 68 pin wide connector. In order to > hook up a 50 pin external device, you *MUST* have a cable that does > *something* intelligent with the upper 18 pins. You case sounds specifically > like your cable wasn't doing anything intelligent with them. Let me state some details about my problem. The 'problematic' DAT is a HP surestore <something> which likes to operate at 10MHz. I've had success with some older Conner DAT operating at 5MHz using the same cable, which has 68-pin micro SCSI on one end and 50-pin centronics-like on the other end. I've also tried to connect the 'problematic' dat to the internal wide SCSI chain using a 68-to-50 pin adapter, which works just great with some narrow HD in another setup. The results were the same (total failure that is). I was suspecting that the termination on the external SCSI chain could be a problem, because I only have passive terminator. But I ruled it out by trying with the internal wide SCSI which is terminated with active terminator. As stated before, the DAT worked just fine, if I connected it to the internal 50-pin connector, even if it wasn't terminated at all. I've tested the same DAT on another system (HP Netserver LC 5/100 with on-board AIC7770 dual channel SCSI host adapter). The symptoms were a bit different, the system did not hang, I only got multiple timeouts while accessing HD (which was on the other channel). Both systems are running Linux 2.0.36 with stock AIC7xxx driver. I've sent a post to the list may be a month ago asking if there's a way to set maximum speed to negotiate for individual SCSI device, but I haven't got any reply. What I wanted to check is to operate the 'problematic' dat at lower speed (eg. 5MHz) in stead of auto-negotiated one. Regards, Metod Kozelj mailto:Metod.Kozelj@rzs-hm.si /\ Ne posiljajte mi smeti ker grizem! http://www.rzs-hm.si/ / \ Don't spam me for I bite! _______________________________________/ \__________________________________ ---- perl -e 'print $i=pack(c5,(41*2),sqrt(7056),(unpack(c,H)-2),oct(115),10);' To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe aic7xxx" in the body of the message
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