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Posted Sun Aug 5, 2012 3:39 PM
Posted Sun Aug 5, 2012 4:37 PM
Posted Sun Aug 5, 2012 5:05 PM
You may want to read Inside Atari DOS by Bill Wilkinson. It contains information about the file structure used for Atari DOS 2.0S.
Hello, all. First time posting here...
I've just completed the long task of transferring all my files over from the 8-bit world into the modern PC world using SIO2PC (a great little tool, highly recommend it) and I unfortunately lost a couple disks due to media rot leaving chunks of surface stuck to the drive heads. From what I gathered, however, only tracks 19 & 20 storing the VTOC sectors seem to have been wrecked, but the actual files are mostly intact, having successfully created an image of the damaged disk. I tried ascertaining where the files start and stop (usually marked by the actual filename like "D:FILENAME.BAS", followed by a character with a decimal value of "16".
Now, I noticed that Individual files that had been successfully pulled from an image all start with three "00" characters and one "01" character. I tried adding this combination of characters to a couple of attempted file recoveries, and it improved their load a little bit (to the point of not giving me an ERROR 120, 21 or 19), but file listings (they're all BASIC files) are jumbled and sometimes crash the emulator I'm trying to run just by simply typing "LIST" to view the source code. It's quite frustrating and I fear my data on a couple of these disks may be permanently lost.
So I guess my question is this - is there a way to manually extract files from an image, assuming that their sectors aren't fragmented? Is there a tell-tale sign letting me know where the physical file start and end is? Many of the files I'm trying to restore are old personal demos that are irreplacable and there are only a small number of them. Any info appreciated. Thanks very much in advance!
Posted Sun Aug 5, 2012 5:17 PM
Posted Sun Aug 12, 2012 6:26 AM
you can try to repair the disks (or ATR images) with Turbo DOS XL/XE and a program on the disk named "Diskfix". It does a much better job than the DOS 2.0/2.5 diskfix, since it can recover a whole directory even when DIR and/or VTOC are damaged or hidden in another sector. I tried it successfully with many disks, some of them did have the files deleted (or with a length of 000 sectors in the DIR), some of them had hidden directories and some even had damaged VTOC...
So, boot Turbo-DOS XL/XE without Basic, as soon as the DOS prompt "D1>" appears type in LOA DIS- (where - stands for the rest of the filename, the same as *.*) and the DOS should load the diskfix program. The program works with 90k / 130k / 180k and (depending on the Turbo DOS version, i.e. 2.1 XF or 2.1 EX) even 360k disks - but 130k must be fully Atari DOS 2.5 compatible and not MyDOS or any other non DOS 2.5 format.
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