TI-99/4A 180K

The TI-99/4A 180K format is a 5 1/4" single-sided, double-density floppy disk format used with Texas Instruments personal computers. Disks had 40 tracks (apparently a variant with 35 tracks also existed) and 18 sectors per track of 256 bytes each (apparently there could be variants with different numbers of sectors and different block sizes). The TI-99/4A file system‎ was used.

Links

 * Info on TI disk formats