Multitos is based on Mint (really old version). FreeMint is much newer/debugged/improved.
I used to use FreeMint on my 520STE with 4MB RAM and 500MB hard disk. It works well.
Mint or FreeMint include a MINT.PRG program (or MINT030.PRG or MINT040.PRG for newer machines). This program should be put in the auto folder, and renamed:
- in MINT.PRG for multitasking with memory protection enabled;
- in MINTNP.PRG for multitasking with memory protection disabled.