Demoscene "NOMEANS" -int13 hack requirements

[joncampbell123]

Describe the bug

The -int13 hack when IMGMOUNTing a floppy disk was added because of an old demoscene trick where the demo hooks INT 13h, and then makes MS-DOS access the in-memory "floppy disk" in RAM through drive A:, supporting that made the demo work.

This demo, http://files.scene.org/get/mirrors/hornet/demos/1994/n/nomeans.zip in demotest, uses the same trick, but does not hook INT 13h if drive A: exists and MS-DOS reports a valid filesystem.

The conclusion here is that the demo will only present it's fake floppy to itself if drive A: exists but MS-DOS reports no floppy is in the drive.

Steps to reproduce the behaviour

Run the demo. Watch it complain about files that clearly don't exist.

I think the demo is doing the drive A: INT 13h interception to present it's own files to itself that way.

Expected behavior

No response

What operating system(s) this bug have occurred on?

Linux

What version(s) of DOSBox-X have this bug?

latest commit

Used configuration

Output log

Additional information

No response

Have you checked that no similar bug report(s) exist?

• I have searched and didn't find any similar bug report.

Code of Conduct & Contributing Guidelines

• I agree to follow the code of conduct and the contributing guidelines.

[joncampbell123]

Ah, drive_fat already has checkDiskChange(), perhaps the call to it could be made before checking the "unformatted" flag, and then checkDiskChange() could check and update the unformatted flag as well as changes or existence of a FAT BPB.