Flashing text in emulated windows XP

[Galvin]

I wrote a simple program years ago in turbo pascal that will enable flashing text in a full screen command prompt in windows xp.

The problem is this only works if windows xp is emulated under virtual PC 2007.

My question is why it doesn't work using VMware workstation or virtualBox?
What is virtual pc 2007 doing different that allows this to work?

 

[TCM]

Try again when the moon is full. This looks like the most reasonable explanation from here.