An 18-sector DOS 3.3?

[bpiltz@gmail.com]

After seeing that Prince of Persia, and a handfull of other Apple programs have a customized 18-sector disk format, I ask the inevitable: Did anyone back in the day attempt to rewrite the DOS 3.3 RTWS to utilize an 18-sector disk format? It does not at all seem like this would be a trivial task, although getting 180kb per 40-track 5.25 disk side would be extremely tempting. How about an 18-sector ProDOS? I know a few have tried half-tracking and 3/4 tracks to increase capacity of a 5.25" DOS 3.3 disks, but did THAT ever get anywhere?

Seems that there is a lot of inefficiency and redundancy on Apple's 6:2 GCR encoding scheme.

Back in the day, I got over 1100 kb on an "dual-sided, dual density" '360 kb' floppy by using full-tracks and 1 sector per track, 88 tracks per disk, and 2350 kb on a 1.44 HD floppy with the same method, and 90 tracks! (God, I loved Alps floppy drives, 10 extra tracks!) That was, of course, MFM encoding on a PC.