There’s Another Possibility (2018)

In the early to mid-1980s, there was a fairly large class of 8086/8088 machines which used DOS (and therefore, FAT-formatted floppies) but were not PC compatible. However, the MSDISK.INC code is only prepared to deal with 512-byte sectors, and can be assumed to be only able to read disks that a PC compatible can read. What we’re looking for is then a 5¼″ or 3½″ floppy using a physical format reasonably close to IBM’s, and formatted with FAT file system, but probably not created on a PC compatible system, and potentially not even created on a system with an x86 CPU.

Source: www.os2museum.com