Hello everybody, One thread of my programm calls the following code: .... %x{ convert -scale '100x100>' -antialias #{src} #{dst} } .... my question is: does this freeze all other threads until the os call is completed? should i use something like fork { %x{ convert -scale '100x100>' -antialias #{src} #{dst} } } } Process.wait instead? Any help appreciated! -g.