[cctalk] LS120, LS240, Floptical Drives and DD, HD, ED, and ?TD? drives

In the golden age of the floppy before its downfall caused by CD-R, CD-RW and flash USB a number of new technologies were introduced to allow for cheap removable storage (Yes MO drives existed but they were expensive). Many of the tech were a great step forward. For example the LS-240 drives from Panasonic/3M (Imation) allowed reading and writing to 120MB, 240MB, 1.44MB, and 720KB disks. They were also compatible with weird formats like IBM's XDF and even allowed the storage of 32MB on a standard 1.44MB floppy disk. To be backwards compatible they used a separate read/write head for regular floppies. However, none of the formats with backward compatibility read or wrote to 2.88MB ED disks. Anybody know why? Was it a licensing issue or the perception that ED compatibility wasn't really required or desired? Or was it technical? I am not sure if ED drives already made use of two read/write heads (one for 720/1.44 and one for 2.88) or just one? If it is the former one could see how it would be hard to have three separate read/write heads in one unit... On a separate note: was a TD (Triple Density) drive ever produced? Apparently the technology existed all the way back in 1989 and would have give 12.5MB on a standard physical sized (3.5") floppy: https://www-computerwoche-de.translate.goog/a/hitachi-maxell-bietet-nec-neue -12-5-mb-floppy-an,1155888?_x_tr_sl=de&_x_tr_tl=en&_x_tr_hl=en&_x_tr_pto=wap p (original in German) -Ali