Hm, strange. Maybe something is mixed up with the FAT?
CHKDSK /F or SCANDISK /ALL /AUTOFIX can help.
Running DEFRAG might also cause the file to be freshly rewritten.

What FreeDOS and DOS 7 have in common is that they know about LBA, and newer partition types.

These are some ideas merely, of course. I don't think you did anything wrong.
I've been through similar situations, when I used another DOS to copy files to an old DOS partition (XDOS).
The native DOS installed on that partition had trouble seeing those files/directories afterwards.

Jo22 wrote on 2023-04-14, 23:36:

Hm, strange. Maybe something is mixed up with the FAT? CHKDSK /F or SCANDISK /ALL /AUTOFIX can help. Running DEFRAG might also c […]
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Hm, strange. Maybe something is mixed up with the FAT?
CHKDSK /F or SCANDISK /ALL /AUTOFIX can help.
Running DEFRAG might also cause the file to be freshly rewritten.

What FreeDOS and DOS 7 have in common is that they know about LBA, and newer partition types.

These are some ideas merely, of course. I don't think you did anything wrong.
I've been through similar situations, when I used another DOS to copy files to an old DOS partition (XDOS).
The native DOS installed on that partition had trouble seeing those files/directories afterwards.

That was my suspicion as well. That is why I tried burning the files to a CD, to eliminate FAT issues.
I tried SCANDISK and DEFRAG now, but it did not help.
I was using a 8gb SD card with 2gb FAT-16 partitions with XT-IDE, connected to a VLB IO card. So I replaced the SD card with an actual 200MB HDD with a single FAT-16 partition, and even replaced the IO card with a 16-bit ISA one, and on another slot for good measures. Still not working :\

That seems like a very annoying problem!

I take it that you can read the file yourself, e.g. copy it elsewhere, maybe even copy it back off the computer and compare it against the original? Given the things you've already tried I imagine that does work.

If the file is otherwise readable but isn't readable to the game, I guess there's a bug in the game. Just speculation: maybe it doesn't deal well with too much memory. Perhaps LOADFIX would help. Or maybe it's related to too much EMS or XMS (I can't recall which it uses, but I seem to recall it does use one).

The plot thickens.
I'm able to play the game in Windows 3.11....
This is what I've done:
Boot to DOS, and the game does not run, as usual. Without rebooting I start Windows by running win /n (to avoid initializing the network stuff). Now the game runs! Either from a dos prompt within Windows, or by running it via the "Run" menu or File Manager. When I exit Windows back to DOS (again, no reboot) the game does not start anymore.
Super weird...

The setup gives the option of using high memory when available, or just base memory. I tried both configurations but did not see difference.
Also booting clean without any drivers, HIMEM, EMM386, SMARTDRV etc, did not seem to make any difference. LOADFIX did not help as well.
Tried flashing any BIOS I could find and playing with any BIOS option I could think of, to no avail.

SOLVED!
The issue was the FILES variable in config.sys.
The default value in DOS 6.22 is 8, which is not enough. https://hwiegman.home.xs4all.nl/msdos2/index.html
I had this value hard coded in my config.sys by Memmaker.... this is why there was no difference between booting "clean" and booting with my configuration 🤦
I realized it when I booted from a custom dos 6.22 boot diskette that had the FILES=30 value configured in config.sys, and to my surprise was able to play the game.
I booted this floppy with F8, manually enabling each line in config.sys until I found the culprit.
What a relief 😀

Note to self (and everyone). Always check FILES variable value, if DOS complains it cannot open a file that is physically there. 😁

Good idea. I remember FILES=20, BUFFERS=30 from the old days.
But considering how many files there are in DOS directory alone...
FILES=50, BUFFERS=60 might be not too overkill. FCBS=4 might be good for extra compatibility, too.

For Windows, STACKS can be increased from 9,256 to 18,512.
It maybe helps if WfW 3.11 is running, with network drivers and lots of software.

If EMM386/MemMaker or QEMM/Optimize are being used, the wasted memory can compensated.

Another alternative might be Cloaking by Helix Software. It moves DOS drivers beyond 1MB..
https://en.wikipedia.org/wiki/DOS_Protected_M … rvices#CLOAKING

PS: It could be that SmartDrive caused FILES/BUFFERS to be reduced.
The disk cache acted kind of as a pseudo replacement, AFAIK.