Mac OS 10.6 - An Overview

On August 28, 2009 Mac OS 10.6, code name Snow Leopard, will be made available for sale. This new operating system represents an incremental improvement in the Mac OS X operating system. Key differences from earlier versions of Mac OS X include

• The first version of the Mac OS for Intel-based Macintoshes. Mac OS 10.6 does not support any PPC-based Macintoshes. To determine whether or not your system is an Intel-based Macintosh selectAbout This Mac from the Apple menu.
  
  
  The type of processor in your computer will appear to the right of the Processor label in the window which appears. All Intel-based Macintoshes will run Mac OS 10.6.
• Mac OS 10.6 is a 64-bit operating system. Not all Intel-based Macintoshes are 64-bit compatible; older Intel Macintoshes will run Mac OS 10.6 in 32-bit mode. For a description of what 64-bit computing means for Mac OS users take a look at Apple's new technologies website.
• Grand Central Dispatch, an "under the hood" technology designed to use the multiple processors in most Intel-based Macintoshes more efficiently. For a description of what Grand Central Dispatch means for Mac OS users take a look at Apple's new technologies website.
• Since Mac OS 10.6 is for Macintoshes with Intel processors all of the code for PPC processors has been taken out of the OS. The result is that Mac OS 10.6 is approximately 7 GB smaller than Mac OS 10.5. Installing Mac OS 10.6 will free up that much space on your hard drive.
• OpenCL allows developers to modify their programs to use the processors built into many Macintoshes to perform general computing tasks in addition to displaying things on the computer screen. Since many new Macintoshes have graphics cards in them which have powerful processors then OpenCL allows applications to use that graphics processor as an extra "computer" and increase the speed at which things are done on the computer. For a description of what OpenCL means for Mac OS users take a look at Apple's new technologies website.
• Quicktime X uses Grand Central Dispatch and OpenCL to dramatically improve the quality and speed of video playback on systems running Mac OS 10.6. The Quicktime media player has been rewritten and incorporates a newer, more modern look. For a description of what Quicktime X means for Mac OS users take a look at Apple's new technologies website.
• Applications that come with Mac OS 10.6, such as iCal, Mail, Safari, Address Book, etc... have been rewritten to be 64 bit applications and will run in 64-bit mode on systems capable of running in 64 bit mode. Older Intel-based Macintoshes running Mac OS 10.6 in 32 bit mode will run these applications in 32-bit mode.

Note: There are several important points to note when considering whether to upgrade to Mac OS 10.6. First, as with all Intel-based Macintoshes, it is not possible to run Classic applications on them. This should not be a problem for users who have already made the switch to an Intel-based Macintosh since those Classic applications would not have ever run on the Intel-based systems but users who are looking to buy new computers should check the applications they use often to make sure they're not running in Classic mode.

Another key change for users who are going to upgrade their system software from Mac OS 10.4.X or Mac OS 10.5.X is that Rosetta, the software package in Intel-based Macintoshes which allow them to run programs compiled to run on the older PPC-based Macintoshes, is not installed by default. In order to install Rosetta-OIT highly recommends it-click on the Customize button which near the bottom left-hand corner of the Install Mac OS X as shown below.Clicking on the Customize button will reveal the window shown below; check the checkbox to the left of Rosetta to tell the installer to install Rosetta.

The Macintosh community is developing a list of applications which are compatible with Mac OS 10.6. While not an exhaustive list and certainly not a final list this list does provide some guidance as to whether some applications are compatible with Mac OS 10.6. Most applications should work without any problems, whereas some applications may need to be updated. For example Adobe has announced they will provide no support for Adobe CS3 applications running under Mac OS 10.6; users will have to upgrade to Adobe CS4 in order to get support. The list may be viewed at wiki link.