Martin Pool gives an informative pros and cons list of Ubuntu Linux versus a number of other OSes. I’d like to jump off on a tangent. Martin gave a plus ot Ubuntu for:

• Less Macintosh historical baggage. Mac apps can be in the wierd state of running but having no windows open: GNOME designers just know this is silly. OS X suffers some friction between the Mac and Unix parts, in e.g. case sensitivity or resource forks. While there is definitely some historical baggage in Mac OS X (not much mind you – Apple were pretty ruthless with cutting things out), the ability for an application to be running without any windows open is actually a design feature and not historical baggage. When described as “the wierd state of running but having no windows open” it sounds downright stupid, but if you describe it as “the ability for the menubar to not disappear suddenly when closing a window” it makes a lot more sense. The Macintosh menubar is placed at the top of the screen because it’s significantly faster to access the menus when it’s placed there (plenty of research backs this up – essentially the sides of the screen have infinite depth so they’re easy to hit). Since the menus are at the top of the screen and not in the window, it makes no sense for the menubar to change when you close a window. Thus, when closing a window in an application the application continues running allowing you to open a new document, adjust preferences etc etc. That’s not the only reason though. Think of someone using pen and paper who has two tasks to complete. They start the first task by getting out a clean sheet of paper and writing on it until they are finished. Then they file that piece of paper away. Finally they start the second task by getting out another clean sheet of paper and starting writing again. In other words, the life cycle is:

1. Create a new document.
2. Work on document.
3. Save and close document (filing both saves the paper and removes it from the workbench)
4. Create a new document. If you were using Gnome, Windows or pretty much any OS other than Mac OS, step 3 would suddenly cause your pen to jump back into the drawer. You’d actually have to rethink the order you do things in to open a new document before you close the previous one. Now you might argue that people typically work on more than one thing at a time and they are likely to have both documents open anyway. They might indeed but in that case there is another subtle benefit. When they decide they’ve had enough of work and want to put it all away and play a game, they simply hit command-Q and all of the documents in that application close. It’s like having a bulldozer that can file things neatly. The disadvantage to the Mac OS way of doing things was that on OS 9, you didn’t realize the application was still running and either ran out of RAM or got really confused when you next double clicked on the application and nothing happened (in fact the menubar changed but noone seems to notice that). OS X (and the magic of modern computing) solves both these problems. Firstly, you won’t run out of RAM anymore because OS X has virtual memory and the ability to move things around in RAM (OS 9 loaded things in order and fragmented memory effectively couldn’t be reclaimed – plus the virtual memory was really bad). You could leave every application on your system open in OS X and it just wouldn’t matter because the unused applications would be paged out to virtual memory. Note that because they are unused they wouldn’t constantly have to be paged back in either so no hard drive thrashing. The second problem is solved in two ways. Firstly there is a reasonably obvious indicator that an application is open (the icon appears in the dock if it wasn’t already there and a black triangle appears under the icon). This helps a little, but not a lot. The biggest improvement is the Aqua Human Interface Guidelines change which now requires that when the user clicks on an application in the dock or double clicks it in the Finder (the same actions used for opening it) the application will bring it’s existing windows to the front if it has any, or create a new window if not. If you combine the effects of these two changes, the result is that the “weird state” of an application being open but with no windows effectively ceases to exist. The user can be completely unaware that the application is running and continue to go about their work without ever noticing. When they try to open the application again it behaves exactly as it would have when first opened and displays a new window. There is no noticeable impact on resources because the RAM can be swapped out to disk and made available to other applications and modern hard drives have plenty of space to cater for this. The user is now able to operate in their logical order without menubars unexpectedly changing on them. So as it turns out it’s the GNOME developers who got the UI design wrong predominately by putting the menubar in the window instead of at the top of the screen. Once they’d made a mess of that behavior, it wasn’t really an option to avoid the disappearing menubar problem because the menu is so inextricably linked to the window.