perhaps this link will help?
https://www.os2world.com/forum/index.php?topic=1033.0
i found it with this search...
https://www.google.com/search?q=os%2F2+unmount+usb+drive
| Sysop: | DaiTengu |
|---|---|
| Location: | Appleton, WI |
| Users: | 1,087 |
| Nodes: | 10 (0 / 10) |
| Uptime: | 99:35:13 |
| Calls: | 13,914 |
| Calls today: | 1 |
| Files: | 187,019 |
| D/L today: |
2,768 files (786M bytes) |
| Messages: | 2,455,499 |