Inside Leopard: Under-the-hood
X11 is a complete X Window System implementation for running X11-based applications on Mac OS X. Or to put it another way, X11 allows for many Linux and Unix applications to be run on the Mac. What sorts of programs? Well, there’s GIMP, a free competitor to Photoshop, or Open Office 2.3, a free alternative to Microsoft’s Office. Neither of these programs have Mac native ports, and yet you can run them on your Mac using X11.
However, if you’re like many other Mac users, you’ve probably never heard of X11, nor seen it on your Mac. That’s because X11 is an optional install; you have to go out of your way to add it during the OS X installation process. And you’d probably only to to the trouble if you already knew you needed X11. (You can add it at any time by re-running the installer and choosing to customize the installation. You’ll find X11 at the bottom of list of programs you can install.)
The biggest change for X11 in Leopard is that it’s now based on a new X11 code base. Whereas prior releases were built around the Xfree86 group’s implementation (release 4.4.0, from 2004), X11 now uses the X.org group’s X11R7.2 code base. (The two groups split in 2004 due to differences regarding language in the X11 license.) Most major Linux distributions have also moved to the X11.org code, so it seems Apple has made the logical move here.
Beyond the new code base, the most visible new feature is a Security tab in X11’s preferences with which you can require authenticated connections and allow connections from network clients.
What we think
I tested GIMP (2.3 and 2.4 release candidate 3) and Open Office 2.3 in X11 on OS X 10.5 on both an Intel-based Mac mini and a Mac Pro, and my results were mixed. Open Office ran fine on both machines, but I had no luck with either version of GIMP on either machine—the 2.4 version would load then quit, while the 2.2 release wouldn’t load at all. I suspect that GIMP will require an update to work with Leopard.
If you need X11, you probably already know you need it, and the new version in OS X 10.5 seems to work just fine—although some of the programs you use may need minor updates to run, as I experienced with GIMP. If you need X11, there’s no reason not to start using the version that’s included with Leopard—just be aware that not all your applications may run without an update.—ROB GRIFFITHS
Disk Utility 11
Perhaps the biggest change to Disk Utility—the built-in application for formatting, analyzing, and repairing the hard drives on your Mac—is its ability to alter the size of disk partitions without losing data.
In previous versions, if you wanted to change the size or number of partitions on a certain drive, Disk Utility would first erase the entire drive and rebuild the partitions as you requested. Now, you can reallocate your disk space to new partitions, or expand existing partitions. This feature lets you maintain separate, bootable partitions for different operating systems, for example. I was able to create, delete, and resize multiple partitions without destroying all of the data on the drive.
Leopard’s Disk Utility also lets you resize disk images. This is a nice feature for those who use Disk Utility to make an empty disk image of, say 100MB, only to find later that they don’t need that much space. They can shrink it down to the proper size and regain that extra space.—JAMES GALBRAITH
[ Rob Griffiths is a senior editor for Macworld . James Galbraith is Macworld Lab director. ]