The Texas Instruments DS990 was a multiuser modular computing system from 1998, based around the TMS-9900 processor (as used by the TI-99). It had an 8" floppy drive module, the FD1000, which was a 77-track, 288-byte sector FM/MFM system with 26 sectors per track. The encoding scheme was very similar to a simplified version of the IBM scheme, but of course not compatible. A double-sided disk would store a very satisfactory 1126kB of data; here's one at old-computers.com:
FluxEngine will read and write these (but only the DSDD MFM variant).
(no options)
To read:
fluxengine read tids990 -s drive:0 -o tids990.img
To write:
fluxengine write tids990 -d drive:0 -i tids990.img