bobmon@iuvax.cs.indiana.edu (RAMontante) (07/30/89)
Hi, everybody --- I'm looking for some words of wisdom about CHKDSK and its error messages. Something has happened to my harddisk over the last week or so, so that when I run CHKDSK I get the "Probable non-DOS disk" message. When I tell it to continue anyway, it eventually produces a report that looks essentially like what I expect (31M total, 49152 in 2 hidden files, 4M free space, etc.). This happens even with a minimal bootup that does nothing fancy --- no device drivers, no drive join or substitution, no tsrs, nothing like that. Further info --- Norton DiskTest says it can read the FAT, system area, and all files, on a sector-by-sector basis with no errors. Can anybody tell me what triggers this message? Especially, what triggers it and then comes up with a clean report? Thanx for any advice, -- Bob Montante (bobmon@cs.indiana.edu) | "Oh dear, I think you'll find Computer Science Department | reality's on the blink again." Indiana University, Bloomington IN | - Marvin The Paranoid Android
Wes@cup.portal.com (Wes H Cowley) (08/01/89)
> ... when I run CHKDSK I get the "Probable non-DOS disk" ... > ... Can anybody tell me what triggers this message? Especially, what > triggers it and then comes up with a clean report? Thanks to the people on Bix who helped me out when I had the exact same problem, I can give you the answer. CHKDSK relys on the first byte of the FAT in generating or not generating that message. Something has overwritten that first byte. In my case I traced it to a compiler that just had to get the last word in when my disk filled up. Unfortunately that it put that word in the FAT. For a hard disk, the first byte should be hex F8. Get into your favorite sector editor, pull up the first FAT sector, and change that byte. The next two or three bytes (depending on whether you have a 12 or 16 bit FAT, with a 30M drive you'll probably have a 16 bit FAT) should be hex FF. > Thanx for any advice, You're welcome, Enjoy... Wes Cowley Internet: wes@cup.portal.com DASNet: [DCI2WC]wcowley Bix: wcowley