Re: [hatari-devel] Floppy images cached?

[Eero Tamminen <oak@xxxxxxxxxxxxxx>]

Hi,

On 30.6.2025 19.14, Thorsten Otto wrote:
> I haven't looked at the code yet, but does Hatari cache the image of floppy
> until i eject them again?

Yes.  If disk contents have been changed when it's ejected (or Hatari 
exits), Hatari overwrites disk image with the in-memory version.


> I just noticed, that when i insert a floppy in Hatari, and at the same time
> try to modify the image from linux using mtools, changes are not reflected in
> Hatari, even when i press "ESC" in the desktop. Same thing the other way
> around: when i delete files from the floppy in the desktop, using mdir they
> are still listed in the image.

There are multiple disk formats, and they can be compressed.  The one 
which subset is supported by mtools, is not handled any differently.

> That is a bit annoying, for every change to the floppy image, it has to be
> ejected/reinserted.

I think reason for that should be fairly obvious.

There's no locking between TOS (or some Atari floppy manipulation 
program) running inside Hatari, and some external program user may run 
outside Hatari to also modify the floppy image FS content directly, or 
any co-operation in how they cache the FS contents.  And I do not see 
how there could...

So mixing of those accesses would be a recipe for disaster (FS corruption).


	- Eero