> The Zire 31 uses Palm OS 5.2. The only Zire that shipped with Palm
> OS 4 was the orignal Zire (m150).

Then they have m150. It's a holiday here, so I can't ask them right now - but 
it's the cheapest model; I think it has only 2 Mb RAM and the screen is B&W 
LCD. It's definitely a Zire and the OS is definitely 4.x, though.

> The OS 4 version probably uses system trap patches to add their
> own notifications when DmCreateDatabase and DmDeleteDatabase are
> called.

Maybe... Hmm, from a cursory glance (my knowledge of the 68K assembly language 
is on the lacking side), they patch the following traps:

sysTrapDmDeleteDatabase
sysTrapSysSetTrapAddress
sysTrapSysGetTrapAddress
sysTrapExgDisconnect
sysTrapExgDBRead

I don't see them patching DmCreateDatabase, so they might be doing something 
slightly different... Still, it's a good idea to patch DmCreateDatabase and 
DmDeleteDatabase during my memory scanning loop, in order to detect that the 
number of databases has changed under OS versions before 5.0; thanks, I'll 
probably do that.

Back to the problem of scanning the memory card. Just as a test, I implemented 
the recursive version that does the whole thing at one go and can't be 
interrupted. It's not a usable approach; I just wanted to test that I 
understand the enumeration process.

Now, under the simulator with an essentially empty card, that worked fine. On a 
real device, though, it hangs after reaching the 337-th file. The card is a 
game card for a PocketPC I took from another colleague (Age of Empires for PPC) 
- but Filez has no problems to examine its contents (although it does show 
bizarre non-ASCII names for a couple of files), so why does my code hang?... It 
not as if there are half a zillion levels of nested directories to cause a 
stack overflow during the recursion - the deepest level is 6, counting the root 
directory too.

Damn. :-((

Regards,
Vesselin
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