So just for kicks I installed both MSDOS6.22 and FreeDos (images under DOSBox), but STILL no Ctrl-Break. So is DOS-Box blocking the interrupt call somehow? Just curious.
By the way, I realize DOSBox is made for gaming, and I use it for that and LOVE IT! But I have also had great success using it for MANY DOS programs (like Turbo Pascal, and a music printing program I love, old word processors, and even an old version of DataCAD, a nice drafting program). DOSBox works flawlessly with all of them! So even though the intent is for gaming, it doesn't change the fact that DOSBox is simply the best, tightest, and easiest to use DOS shell out there, for ANY purpose. So it just seems logical to me that it would be great to improve it further, even if the gain is only loosely applicable to the gaming world.
All the best, and thanks for a wonderful gift to those of us trapped in the past.
PS - I also installed BOCHS and it TOO doesn't allow Ctrl-Break. The only way it works is with icky NTVDM under XP.