![Sad :(](./images/smilies/icon_sad.gif)
I have to say that I consider it a serious flaw in the design of an operating system that it doesn't keep track of, has no way to tell, how many instances of a program are running. As far as I know, no operating system has this as a fundamental feature of its design.
![Confused :?](./images/smilies/icon_confused.gif)