I have a 512GByte SATA drive formatted as FAT-32 (no easy trick) running DOS 7.1, ie WIN98se booted into real mode. The computer is a Panasonic CF-52 Toughbook, has native USB support in real-mode DOS.
SO: I can boot the computer off a Floppy Drive; off a USB memory Stick; or off an SD card or CF card in a USB reader. Put Phar Lap TNT.exe and run executables that use up to 4GBytes of memory, and have a self contained VMM handler.
The DOS7.1 system, executable, TNT.exe, and VMMDRV.exp all fit on a floppy. Of course using the Floppy for a page file is kind of slow.
REACTOS "looks interesting"- but not much documentation regarding supported disk formats, dual-boot capability, supported devices.
FreeDos is worth a look for you. A combination of FreeDos FDISK, FreeDOS Format, and Win98 Format were used to make the booatable SATA 512GByte drive.
Edited by BrianVS, 17 September 2016 - 08:01 PM.