Date: Mon, 18 Nov 1996 18:27:56 -0600 From: zach@blizzard.gaffaneys.com (Zach Heilig) To: questions@freebsd.org Subject: SCSI wierdness Message-ID: <Mutt.19961118182756.zach@murkwood.gaffaneys.com>
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Sorry for the somewhat long rambling mail, but my mind is a bit boggled at the moment. I mailed something a little while back, concerning a drive not booting from a TekRam DC390F controller, but appearantly working correctly with a Future Domain TMC-850. The drive will still not boot with the TekRam controller, but it works perfectly fine with the Future Domain controller. I was able to low-level format the drive with the TekRam controller with the dos driver, repartition it with the FreeBSD 2.2-ALPHA installation floppy, and proceeded to install FreeBSD 2.2-ALPHA. If I install the kernel on a bootable floppy, and boot with the "-r" option (is there any way to make that default?), everything seems to work ok. Having only a partially working setup bothers me quite a bit, but since the drive is about four times faster with the TekRam controller, I've been putting up with the slower boot from floppy. I did some checking, and even though the manual doesn't explicitly say you need the boot drive to be SCSI ID 0, some other general SCSI documentation I have says that some SCSI controllers (usually the ASPI type, which the TekRam is) require the boot drive to be jumperd for drive ID 0. I also noted that all the examples in the manual have one drive with a SCSI ID of 0. I noticed the drive was ID 1, so I rejumpered it to ID 0. While I had the drive out, I thought on a whim to check on the SCSI terminators, and to my utter surprise, there were NO TERMINATORS!!! I did a little running around town, and picked up a set of terminators, and installed them. After the terminators were installed, neither controller would recognize the drive, and the ncr0 probe would mumble something about a fatal error (some command failed... don't have the error handy...), and it put up a resetting controller on the screen and did not continue. I pulled the terminators... they were somewhat warm, bordering on hot... a sign something isn't quite right :-). Everything worked again after I powered up, except no boot from the TekRam controller as agravatingly usual. This is a rather strange situation, as you will probably agree, so I called up seagate tech support (I have an st1480n drive) and explained my situation to the person at the other end, and I heard a pause. After explaining that I only have the drive and the controller on that bus, he went to check on which terminators that particular model requires. When he came back on the line, he said it took a non-standard terminator value (330 ohm, instead of the normal 110 ohm terminators). He then said that even though the setup should not be working, I probably wouldn't be hurting anything to run it that way. (my thoughts are that if it isn't supposed to be working, it hasn't been tested that way, and how can you be sure that nothing will be damaged... then I remember that I've run it about 9 months, 24 hours a day, 7 days a week with no resisters, and I feel a _wee_ bit better.) That explains why the terminators I came up with didn't work, and I found that nobody in town has the correct ones. It does not explain why the setup does indeed work. Anyone know where I can get 330 ohm terminating resisters? It doesn't give me a warm fuzzy feeling to run drive without resisters. -- Zach Heilig (zach@blizzard.gaffaneys.com) | ALL unsolicited commercial email Support bacteria -- it's the | is unwelcome. I avoid dealing only culture some people have! | with companies that email ads.
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