they might be reading/accessing the "harddrive" with interrupt 13 which doesn't do much on regular mounted drives. The games might work if they are placed on an image drive.

I tried copying the files to a real floppy and then mounting the floppy in DOSBox (with -t floppy), but that didn't make any difference.

Anyway, I just tried mounting an image of that floppy (made with Rawrite) using imgmount. This is what I get in the debug window:

1   1992876: FILES:file open command 0 file knight.EXE
2Seek to 0 with type 0 (absolute value 0)
3Seek to 4096 with type 0 (absolute value 4096)
4Seek to 34 with type 0 (absolute value 34)
5   1997301: BIOS:Disk 1 not active
6   1997397: BIOS:Disk 1 not active
7   1997520: BIOS:Disk 1 not active
8   1997616: BIOS:Disk 1 not active

And the error message turns into

1INVALID DISK! err#3-0001

which is at least more than I've gotten with any other method.

The game's files take up 615 KB; maybe it has to be a 720K floppy. Would Disk 1 here be Drive Z?

Try mounting a image on both a and b

Although it seems a bit of copyright protection. does it work in a different OS ?(windows for example ?)

At the Windows 2000 command prompt, running Knight.exe from my hard drive causes it to access the floppy drive. After a few moments the command prompt just comes up again, though, without any "Invalid Disk" message. Same thing happens when I run knight.exe from the floppy.

In DOSBox, if I mount the floppy image and mount the hard drive directory where I have the game and then try to run it from the hard drive, I get

1    989044: FILES:file open command 0 file knight.EXE
2    993458: BIOS:Disk 1 not active
3    993554: BIOS:Disk 1 not active
4    993677: BIOS:Disk 1 not active
5    993773: BIOS:Disk 1 not active

What else could Disk 1 be?

the second floppy disk.

I guess I forgot to mention that mounting an image as B in DOSBox doesn't change anything.

If I try to run the game under Windows 98 (from the hard drive, with floppy in drive A, from MS-DOS Prompt or in MS-DOS mode), I can get err#2-0200. If I try that with a Zip disk inserted (my Zip drive is drive B in Windows 98), this changes to err#4-0200, and I do see the light flicker on the Zip drive for a moment.

Maybe this game can only function properly on computers with a single floppy drive. Is there some way I can make DOSBox report Drive 1 as being completely nonexistent?

...Then again, maybe not. I just tried mucking about with some single-floppy configurations in Bochs and didn't get anywhere either.

I guess this probably is some sort of copy protection scheme, and the Windows 2000 command prompt just doesn't support whatever method it's trying to use to read the floppy. Oh well.

Copy protection. I fixed this for my personal collection some years ago (thanks to Peterferrie). You definitely need a cracked exe...

In all these years I only found two websites providing a working pc version, happy hunt and google is your friend 😉