Path: utzoo!mnetor!uunet!mcvax!unido!tub!actisb!federico From: federico@actisb.UUCP (Federico Heinz) Newsgroups: comp.sys.atari.st Subject: Strange bug in FAT allocation Message-ID: <211@actisb.UUCP> Date: 29 Apr 88 10:19:13 GMT Reply-To: federico@actisb.UUCP (Federico Heinz) Organization: Actis in Berlin GmbH, W. Germany Lines: 54 There are times when I wish I had taken kite construction or chess as a hobby. But I've chosen computers, and sometimes things like this happen. A couple of days ago, I formatted a diskette with DCFORMAT, 80 tracks, 9 sectors, and wrote an MS-DOS boot sector to it. Then I went back to the desktop, grabbed three files from the hard disk and placed them over the floppy icon. When the copy operation was ready, I opened the floppy icon "just to make sure". Good I did: the title bar showed "0 Bytes in 0 Files", and the window was really empty. I tried again (starting at the formatting stage), the same thing happened, the third time it worked. By the same time, some weird things started to happen whit my floppy drive: one and the same disk would show, when inserted, either absolute garbage (filenames with commas, arrows, happy faces, etc) or the correct directory. The next time the "vanishing copied file" effect showed, I decided to inspect the disk. I found something pretty strange: the boot sector information (both TOS and MS-DOS) says that the floppy has 5-sector FATs, although 3 sectors would suffice. Then I discovered why no files were found. The boot sector information said 5-sector FATs and 7-sector root directory, in other words: Boot sector #: 0 First FAT starts at: 1 Second FAT starts at: 6 Root starts at: 11 First avail. cluster: 18 but looking at the first sectors of the floopy I saw that the names of the files I had copied were written in sector #7, and that the first allocated cluster started in sector #14, which are the correct values for a 3-sector FAT disk! I have come to some conclusions, but I don't think that I've got the complete picture. I have determined that DCFORMAT's idea of using 5-sector FATs is a bug, but not a fatal one. It gives away 2 clusters (2 KBytes) that could be used for data, but that's about it, it souldn't have any malign effects. It looks like somebody deep in the OS doesn't notice this FAT size change, and screws the whole thing up. My two questions now are: WHY doesn't my cute little Isabelle (that's my Mega's name) notice the FAT size change? And why does this happen NOW? It has worked fine all the time until now. The third question is why does it happen to ME, but I think this is a bit egocentrical. Any ideas? -- Federico Heinz "In Dubio Pro Libido" BIX: fheinz | Beusselstr. 21 UUCP: ...!unido!tub!actisb!federico | 1000 Berlin 21 Tel: (030) 396 77 92 | F.R. Germany.