Back in the 1980's, hundreds of Atari user groups formed throughout the United States. One of them, The Atari Computer Enthusiasts of Columbus, Ohio preserved the majority of their newsletters (which you can find on archive.org) and their "Disks of the Month" (342 images which you can find on the Pooldisk under the directory ACE). Just like the Bellcom archive I've been digging into, the preservation of some of the disks wasn't perfect. So let's spot a few corrupted images and see what we can do to fix them.
The first disk that caught my eye was acec111h.atr. This disk has the 850 Express program on it, but when I was validating the sector links, the DOS.SYS on the disk was incomplete. Dumping the sectors I noticed almost immediately that sectors 21-36 appeared to be backwards. We saw the exact same kind of damage on Bellcom disk 349 involving the same sectors, so we can fix it that same way (and continue to puzzle how the disk degrades in that particular way):
c:atr.pl -copy orig.atr acec111h.atr 36 21 0 c:atr.pl -copy orig.atr acec111h.atr 35 22 0 … c:atr.pl -copy orig.atr acec111h.atr 21 36 0Another interesting disk is acec069a.atr. All the sectors from 700 up are empty, but judging from the directory, sectors 700-713 should have data on them (parts of two documentation files, DOC.TXT and DRONE.TXT). By searching through the rest of the pooldisk, I find the same content on ANTIC88_SEP_A.ATR. The only difference is the equivalent files on the ANTIC disk are one sector longer. Looking at those sectors, it's likely the files were truncated a bit to fix them, as the ends of the files don't quite look right. So to restore this disk, I take the equivalent sectors from the ANTIC disk, and manually decide where to end them.
c:atr.pl -copy E:ANTIC88_SEP_A.ATR acec069a.atr 230 713 0 + manually fix link to 14 00 5c c:atr.pl -copy E:ANTIC88_SEP_A.ATR acec069a.atr 229 712 1 c:atr.pl -copy E:ANTIC88_SEP_A.ATR acec069a.atr 228 711 1 c:atr.pl -copy E:ANTIC88_SEP_A.ATR acec069a.atr 270 710 0 + manually fix link to 4c 00 45 c:atr.pl -copy E:ANTIC88_SEP_A.ATR acec069a.atr 269 709 1 ... c:atr.pl -copy E:ANTIC88_SEP_A.ATR acec069a.atr 260 700 1One last disk for today, acec068b.atr. Sectors 613 and 614 are empty, breaking RUBICUBE. A similar file exist on disk acec016a.atr, so we can restore the BASIC program via.
c:atr.pl -copy acec016a.atr acec068b.atr 206 614 1 c:atr.pl -copy acec016a.atr acec068b.atr 205 613 1
We'll look at some other disks in the future.
Number of downloads: 1