From owner-freebsd-hackers Fri Jan 14 11:44:59 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from monkeys.com (i180.value.net [206.14.136.180]) by hub.freebsd.org (Postfix) with ESMTP id 4ABE314CDE for ; Fri, 14 Jan 2000 11:44:56 -0800 (PST) (envelope-from rfg@monkeys.com) Received: from monkeys.com (localhost [127.0.0.1]) by monkeys.com (8.9.3/8.9.3) with ESMTP id LAA54649; Fri, 14 Jan 2000 11:44:51 -0800 (PST) To: Jim Shankland Cc: hackers@FreeBSD.ORG Subject: Re: "very dangerously dedicated mode" is In-reply-to: Your message of Fri, 14 Jan 2000 10:25:28 -0800. <200001141825.KAA18379@biggusdiskus.flyingfox.com> Date: Fri, 14 Jan 2000 11:44:51 -0800 Message-ID: <54647.947879091@monkeys.com> From: "Ronald F. Guilmette" Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG In message <200001141825.KAA18379@biggusdiskus.flyingfox.com>, Jim Shankland wrote: >By the way, I also struck out with DOS fdisk: it took one look >at the garbage partition table, and wedged. I'll be trying a >Linux rescue disk next. If that fails, too, then I seem to >have generated a 1-Gigabyte hockey puck (you didn't think I >was trying this with a new disk, did you)? > >Anyway, now you know, my friends, how "very dangerously dedicated mode" >got its name :-). Is this disk by any chance a SCSI drive? I also managed to seriously snafu one SCSI drive that I was playing around with recently. I don't think that my situation was quite as bad as your's, but it was close. The FreeBSD FAQ (Installation section) has some very good info about the ins and outs of SCSI disk geometry. It's very much worth reading if you are working with SCSI drives. See: http://www.freebsd.org/FAQ/install.html#GEOMETRY One fact that I found out the hard way however... and that ISN'T in the FAQ... is that if you have a SCSI drive that was low-level formatted while your SCSI _controller_ was set with ``BIOS address translation'' either on or off, and if you then _change_ this SCSI controller setting (off -> on, or on -> off) and then try to use the previously-low-level- formatted drive on the controller while it is set that way, you may per- haps experience some grief. I had one SCSI drive in a system that was working perfectly well, and then I tried to add another _identical model_ drive from a different system and every tool I used to tell me what the second drive believed its geometry to be showed the geomery for the drive as being clearly incorrect... according to the info contained in the FAQ page at the above URL... for the current translation/non-translation setting of my SCSI controller. Fortunately, the SCSI controller in question was a non-cheap Adaptec. Every Adaptech that has a model number >= 1520 (I think) has on-card built-in ROM-based utilities, and among these is a low-level formatting utility. I ran that on the drive in question and it cured it... the thing started to act like it had a proper sort of geometry (based upon the current translation/non-translation setting of the controller) after that, and all was well again. I then partitioned the drive normally (using DOS fdisk) and it has been just fine ever since. Apparently, SCSI drives for PeeCee-type system really just DO NOT like to be moved from one SCSI controller to another if the two controllers have different translation/non-translation settings. P.S. I don't know if any of this has a damn thing to do with _your_ specific problem, but I felt like sharing this tiny bit of hard-won knowledge anyway. To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message