************************************************************************** * The following message thread appeared on the Computer Connection BBS * * in Washington, DC (202-547-2008) and offers an explanation to a * * problem which I and others have experienced....the DOS error message * * "File allocation table bad, drive A" * ************************************************************************** Date: 02-05-87 (05:42) Number: 1130 To: ALL Refer#: NONE From: RICH SCHINNELL Read: (N/A) Subj: PC DOS 3.2 AND MS DOS 2.1 Status: PUBLIC MESSAGE If you are using IBM DOS 3.2 and you seem to have problems reading disks that were formatted on other machines running other versions of DOS, the following is for you: IBM PC-DOS 3.2 has a fatal problem reading disks that have been formatted under some versions of MS-DOS 2.11.(I have not had an opportunity to check other version). Based on tests that I have run, the boot record that MS-DOS 2+ places on a diskette when formatting makes the diskette un-readable as a valid disk by PC-DOS 3.2. Whenever you try to do a DIR on the diskette you will get the following: . Volume in Drive A is: "from here on you get Garbage directory entries" and then the message: "File allocation table bad, drive A" . That diskette drive will no longer read any disk as you will always get the same message even though you place a known good disk in the same drive and repeat the DIR command. Red Switch time. These same MS DOS formatted diskettes are readable by all other versions of PC-DOS except 3.2. NORTON utilities 3.1 and DOS 3.2 go wild when you try to run the NU program on this disk. "Red switch time again". . PC-DOS 3.2 will read as valid any disk formatted under other versions of PC-DOS. If you are going to swap data between machines running MS-DOS and IBM PC-DOS 3.2 then a solution would be to format disks under IBM DOS and then copy files onto these diskettes on your MS DOS machine. Date: 02-06-87 (00:33) Number: 1145 To: RICH SCHINNELL Refer#: 1130 From: JAMES AUSTIN Read: YES Subj: PC DOS 3.2 AND MS DOS 2.1 Status: PUBLIC MESSAGE I have read about a similar problem, though the description I saw was not as serious as what you've described. What I read was that this is DELIBERATE on the part of IBM. PC-DOS 3.2 supposedly looks for IBM's copyright notice in the formatting on track 0, and will fail to read a floppy missing that notice. Since a compatible's version of MS-DOS won't format with an IBM copyright notice, this means only a floppy from another IBM running PC-DOS will work with PC-DOS 3.2, though I hadn't heard about the system literally hanging when this is tried. Of course, IBM is not obligated to support anyone else's implementation of MS-DOS, and this is the sort of petty anti-competetive gesture one expects in the early stages of an IBM market crush operation. If this is really the problem, I suppose it might be nearly a month before a PD utility to write a convincing message string at the front of an MS-DOS disk appears. Date: 02-06-87 (19:24) Number: 1167 To: JAMES AUSTIN Refer#: 1145 From: MIKE FOCKE Read: YES Subj: PC DOS 3.2 AND MS DOS 2.1 Status: PUBLIC MESSAGE The Leading Edge Model M's DOS had the problem of not putting out whatever was being looked for and there is a PD "patch-it-up" floating around that I first saw about three months ago. Unfortunately, don't remember the name. Date: 02-06-87 (22:53) Number: 1169 To: JAMES AUSTIN Refer#: 1145 From: JOHN CRAVEN Read: YES Subj: PC DOS 3.2 AND MS DOS 2.1 Status: PUBLIC MESSAGE That's interesting! I took a look thru Compaq DOS 3.1 and it has the words IBM and files IBMDOS.COM and IBMSYS.COM as if it were IBM rather than MS DOS. Guess they knew somwthing that most of us did not. They don't seem to be worried about using the characters IBM on their DOS diskettes. I guess that one can name their files anything they want to!