A short list of features so far:
* Easy multiboot with Win2000/XP
* FAT 32 file system and large disk support
* LFN support (on command line with 4DOS)
* LBACACHE - disc cache
* Memory Manager
* FDCDEX and CD-ROM driver
* Mouse driver with wheel-support
* FDAMP - APM control/info, energy saving TSR/control, cache flush, rebooting
* UDMA driver - UDMA driver for DOS: up to 4 unlimited size hard drives
* etc.
