Date: Wed, 14 Mar 2001 00:29:26 -0600 From: Rob McGee To: opendos AT delorie DOT com Subject: [ot] disk geometry mismatch? Message-ID: <20010314002926.B3024@sl7> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.2.2i Sender: ws AT room101 DOT 2y DOT net Reply-To: opendos AT delorie DOT com ** This isn't even remotely DR-DOS related. But if anyone can figure out ** this problem, it would be you people. :) Replies off list would be ** very much appreciated. (Or on list if you think it's interesting.) This is indeed a puzzlement. Our eldest kid got a gift computer. It cruised along okay for months, despite a few warning signs: RAM failed POST, unable to warm reboot, didn't report disk size and free information as an SMB share. But it would easily go at least 1-3 days between reboots, and considering it was running Win95 (OSR2) that is not too bad. So I blew off doing anything about the problems. Sometime yesterday, while unattended, it died. I had seen it running a screensaver in the morning. She came to do something in the afternoon but got no picture. When she turned it on for me I could tell it wasn't booting: no video initialization, not even a beep code error. I tried disconnecting everything but the video: cards, power & interface cables. I swapped the RAM. I swapped the video card. I swapped the CPU (yes, absolutely sure the jumpers were correct.) Still no flicker, still no beep. 'E's pinin' for the fjords. Beautiful bird, the Norwegian Blue. I put most of the same peripherals on a different motherboard with a different CPU and RAM. In getting it to work, physically, I found I could no longer access the hard drive. It's a WDC AC35100L which is C/H/S 10672/15/63, LBA'ed to 627/255/63. Identify drive from a Linux boot message says "10085040 sectors (5164MB)". DOS fdisk said: "C: partition 1, active, PRI DOS type, no volume label, 4918MB, system unknown, usage 100%." It goes on to say the total disk space is 4910MB, 8 less than the partition. That sounds odd. Figuring "(sectors * 512) / 1024^2" I get 4924.3359MB. I had a CD of Norton Util. 95 v. 2 (FAT32-aware) and tried ndd.exe. It offered to try to recover a partition of 812MB. I declined the offer and tried diskedit.exe instead. The first 63 sectors were all 0's. (63 spt, of course. Is that normal?) The 64th sector showed what looked to my untrained eye like some filesystem information. There was a string "FAT32" and the volume label as it was before the crash. I asked diskedit to try to create a virtual filesystem of this, and again, it offered something in the 800MB range. Furthermore it said it would be FAT16. But that's not right, it was all in one big FAT32 partition. I tried changing some of the parameters around, but could not find anything that worked. Since I really don't know what I am doing I feel like I'm looking for the proverbial needle in a haystack. Somewhere along in there I tried "fdisk /mbr" too. Finally this afternoon I came up with the hypothesis of a disk geometry mismatch. That some parameters had been manually entered in the dead motherboard's CMOS settings, and they weren't quite correct, but close enough that the drive went along with it. Does this hypothesis sound right? If so is there anywhere I might be able to find a clue about the disk geometry parameters used? I'm afraid that my "fdisk /mbr" might have rendered the thing unbootable though. It's nothing major, but if there's any way to recover this I sure would like to do it. If you read this far, thank you for your time. If not, I'm sorry for the disruption. :) Rob - /dev/rob0