>Perhaps another option would be for the VM process to create a second small 
>"lock file" whenever the changes file is open for write, and remove it when 
>it's closed or the process exits. On startup, VM would check if the lock file 
>exists, if it does, will not start. Of course there is the problem of crashes 
>.. 
>  
>

<geezer voice>
Sonny boy, when I was your age. We had this new-fangled DOS program 
called "share.exe". It would keep track of the files you opened, and 
make sure they weren't opened again. The application programmers didn't 
have to do squat. Only problem was, when you got bit by a file-handle 
leak. =(
</geezer voice>