When I do a simple "echo test>test.txt" command in ms-dos in my emulator, the floppy becomes corrupt and unbootable (fresh ms-dos 3.3 floppy disk image which is working and booting). Is there anything wrong with my floppy disk write command, or is the CPU doing wrong calculations/memory writes/reads?

My project is at:
https://bitbucket.org/superfury/x86emu

The floppy disk image I'm using is at:
http://www.allbootdisks.com/downloads/Disks/M … ages/Dos3.3.img