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Pulling files out of .ATR images


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#1 137th Gebirg OFFLINE  

137th Gebirg

    Combat Commando

  • 2 posts

Posted Sun Aug 5, 2012 3:39 PM

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!

#2 CharlieChaplin OFFLINE  

CharlieChaplin

    Stargunner

  • 1,666 posts

Posted Sun Aug 5, 2012 4:37 PM

Afaik,

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.

When the diskfix program has loaded you can set drive 1-4 for scanning the damaged disk by simply pressing RETURN. Use the arrow-keys (without Control-key) until you reach "Recover Directory" and press Return. The program will now scan your damaged disk and when done, it will present all the files it has found. The files will usually be named FILE001.REC, FILE002.REC, etc. (the program can detect COM, BAS and TXT files and set the extender accordingly; all other files will get the extender REC; but from time to time even BAS files will get the extender REC - just REName them using REN *.REC,*.BAS/N ). When the program is finished with scanning, it will ask you to save the new DIR and VTOC, just press Return to do so.

NOTE: The diskfix program will only work correct on disks with files or better DOS 2.x files; it will show strange things, when scanning a bootdisk or a non-DOS 2 diskette (lots of files with 1 secor length each or other strange things). Next, when scanning / recovering a whole directory, the program will only scan for files that are/were on the disk, it will not test if the files are partially damaged or overwritten or if there is a file-number mismatch (Error 164). To test the files, try another diskfix option, named "Verify DISK(files)", this function may or may not repair a) files that show Error 164 or b) DIR/VTOC that shows false free sectors (e.g. 999+ FREE SECTORS on a disk that is filled with many files or just 90k / 707 sectors in size)...

To speed up the "Recover Directory" or "Verify Disk" process, load Turbo-DOS and its diskfix program under emulation and set the emulator to full speed. Attached Turbo-DOS 2.1 NT here (where NT stands for normal and turbo, max. 180k disks and there is no built-in speeder in this version; type HEL or use the XL/XE help key to display all Turbo-DOS commands)... GOOD LUCK !! -Andreas Koch.

P.S.: To pull out files from ATR images you can use PC programs like UnmakATR by Ken Siders, MakeATR by Soudi and many others - but the ATR must have a valid DIR and VTOC then; since this seems not to be the case with your disks, you have to repair them first using e.g. Turbo-DOS and its Diskfix program...

Attached Files



#3 BillC OFFLINE  

BillC

    Dragonstomper

  • 994 posts
  • Location:BC Canada

Posted Sun Aug 5, 2012 5:05 PM

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!

You may want to read Inside Atari DOS by Bill Wilkinson. It contains information about the file structure used for Atari DOS 2.0S.

The following image is from Chapter 2:
Posted Image




#4 137th Gebirg OFFLINE  

137th Gebirg

    Combat Commando

  • Topic Starter
  • 2 posts

Posted Sun Aug 5, 2012 5:17 PM

That did the trick! Most of my old files were successfully loaded. Thank you VERY much!

#5 Larry OFFLINE  

Larry

    River Patroller

  • 2,371 posts
  • Location:U.S. -- Midwest

Posted Sun Aug 12, 2012 6:26 AM

Hi Andreas-

Thanks for posting the handy DISKFIX tool -- that is an impressive utility!

Afaik,

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.

(snip...)






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