Hi, anyone knows which is the minimun size of stack required to get DOS programs be able to call ints without any problems? It's safe 64 bytes of stack?

I don't know. It'll depend on your DOS version and on which interrupts you're going to call. Usually, DOS interrupts will not eat that much stack, but if you're calling mouse driver interrupt or EMS interrupt services, you will most likely need a little more. Anyway, even if you find your application runs always fun with 64 bytes of stack that may not be the same after you load a TSR that may get hooked from those interrupt vectors. I'd suggest a little more... say, to feel it safe, at least 256 bytes. But that is just my own opinion.

OK, I will set 256 bytes then, thanks Cas

256 bytes is better than 64, but IIRC there are some known problems with CWSDPMI on certain conditions because it supplies a default real-mode stack of just 256. To be on the safe side a stack of 512 should be supplied.

Thanks for the info Japheth!!