Universal Image Options and Potential Issues
Several people have reported creating a universal Mac OS X installation that can be used to boot both Intel and Power PC Macs. Although I think that this is a great achievement, it is not something that I suggest administrators attempt in a live environment. The process is not supported and might cause unknown issues.
One known problem with such installations is that they have problems identifying and accepting software updates because the process of creating them involves mixing the components of both Intel and Power PC Mac OS X releases. The resulting configuration cannot properly identify as either release and therefore cannot work with Apple’s Software Update service. Even downloading and applying the update by hand might not work because there are typically differences between Power PC and Intel updates, and only one is likely to be able to update the home-grown installation (if either is able) and one might not address all the issues intended by the update.
There is also a general concern about stability and unknown potential issues. In addition to their different partition schemes, the Intel and Power PC releases of Mac OS X also include varying drivers for specific hardware that have not been significantly tested against the opposing platform’s hardware. Although much of the hardware is similar, and the methods I’m aware of for achieving a universal installation do include drivers from both platforms, there is no guarantee that this approach will yield a stable platform with all hardware.
Even in the absence of problems created by developing a home-grown universal installation, there are likely to be more issues when troubleshooting. Many troubleshooting steps rely on specific files within Mac OS X. In a combined system, it might be difficult to rule out where a problem exists because you have an added layer of complexity. And because you are dealing with an unsupported product, you run the risk of voiding any Apple service agreements for your technical staff and users to resolve problems (for example, if someone should given an Intel Mac OS X build number to an AppleCare rep when calling about a Power PC machine), even if those problems relate to iMovie or Final Cut Pro or something completely unrelated to the home-grown installation.
Although the idea of creating a universal image might sound like a savings on resources, it has the potential to actually cost more resources if something goes wrong (be it with the installation itself or some unrelated issue) or to ensure updated stability and security. Although maintaining additional images might be more work, the more responsible approach is to work with your existing allocation of workstations, resources, and processes to minimize the amount of extra effort required until a universal release of Mac OS X is available.
If you do opt to attempt a home-grown solution, I strongly suggest that you use it only for testing and administrative purposes. One creative use that should have minimal impact on your environment is to use a universal installation in a bootable external drive used for troubleshooting. If you do choose to deploy such an image, do so only after extreme testing. Be certain that the users in the environment understand that they are using a home-developed installation and that there could be unforeseen issues.
Although I do not support this approach, the following resources contain information about how to create a universal Mac OS X installation: