Once an application is first launched in OS X from the dock, it stays open in the background, even after you close all open windows for that application. For example, if I open Google Chrome from the dock and start a session with 3 windows, then close all of those windows when finished with them, the Chrome icon will retain the small dot under its dock icon signifying that it is still 'open in the background'. This makes opening further windows for that application almost instant, rather than having to reload the application every time to create a new window. I am wondering if it is possible to implement this feature in a Linux environment, as I have not found a way to do so.
Note that I am only talking about the application launching mechanism, I am aware of Docky and other programs that simulate the OS X dock, but I have not yet came across a way to make Linux exhibit this preloading behaviour.