Found a X-DOS 5.2 kernel here https://archive.org/download/ipadDOS not sure it's the latest...

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X-DOS 5.2 from HBS isn't included:
-It didn't support multiconfig commands
-The boot managers I test didn't work (BOOT, MCONFIG, MULTICNF)
-It didn't support the Candyman Multi Bootsector loader.
-The RAMDISKes I use didn't work (XSMDSK, RDISK)

ZDOS 1.68 y ZEBOR Technology isn't included:
-It didn't support multiconfig commands
-The boot managers I test didn't work (BOOT, MCONFIG, MULTICNF)
-The RAMDISKes I use didn't work (XSMDSK, RDISK)

Just for the record, both ZDOS and X-DOS are neat.
They just don't mimic MS-DOS in every aspect, but do their own thing.

X-DOS has built-in XMS support, a colourful CLI and some internal graphical utilities (external utilities missing in 'free' versions).

ZDOS is a 32-Bit OS meant to be run in tandem with the 32-Bit ZBIOS, to ideally run its own 32-Bit applications.
16-Bit DOS programs are supported in some dedicated VM.

To give an idea:

ZBIOS exels in disk I/O which dramatically decreases the time spent booting an OS.
As an example, our floppy disk emulator used for CD-ROM/DVD booting reads data more than 53 times faster on a 133MHz 486-based board when compared to a 1.5GHz Athlon XP with a standard BIOS.

ZDOS was developed as a 32-bit replacement of 16-bit DOS,
but with modern features like multi tasking, demand paging, SMP etc..

ZDOS is fully backward compatible with 16-bit applications using BIOS and DOS APIs.
These BIOS and DOS calls are handled entirely by 32-bit code,
leaving more memory available between 640K to 1MB, since ZDOS maps locations used by the 16-bit BIOSes to upper memory blocks.

Old 16-bit applications runs in their own virtual machines in parallell with 32-bit processes.

No offense, but this thing is from 20 years ago and has more sophistication than FreeDOS has now.
Imagine how great and fun DOS as a platform would be now if something like ZDOS have had a community.

With ZDOS you can do every thing you used to do, but now in a full 32-bit, multitasking environment.
You can create 32-bit, multi tasking processes with a lot of threads, invoking safe reentrant 32-bit BIOS and DOS API calls.

PS: To those who may think that this is just a footnote in history..

[..] In October, six Stockholm-based companies were selected to take part in an event in Hong Kong where Chinese investors, indu […]
Show full quote

[..]
In October, six Stockholm-based companies were selected to take part in an event in Hong Kong where Chinese investors,
industry players and reporters met with Swedish cleantech entrepreneurs.

The companies came from a diverse range of industries including clean technology solutions in renewable energy,
waste management and construction, as well as computer engineering.

[..]
One of the companies was Zebor Technology, which has developed the fastest, most cost-effective and scaleable platform for embedded systems based on the products ZDOS and ZBIOS.

Source: https://scandasia.com/9985-china-seeks-swedis … tech-expertise/