Reader Hugh Fredericks seeks a new Mac, but with an old OS. He writes:
I love the look of the new retina display MacBook Pro, but I'm not sold on Lion. Is there any way I can run Snow Leopard on this new Apple laptop?
Almost assuredly not. To begin with, the new MacBook Pro includes software that allows for all the high-resolution goodness that you find so attractive. That would be missing from Snow Leopard. More broadly, with the MacBook Air, Apple set upon a path to ensure that the OS version that ships with its laptops is the baseline for that machine. You can go forward in the form of Mountain Lion when it ships, but you can't go back to a previous version such as Snow Leopard. (This is largely about video drivers present in Lion that are missing in Snow Leopard.) The same applies to new Mac minis.
My understanding is that the iMac is a different case. But it's not a slam dunk. You can't install Snow Leopard on a new iMac with an old Snow Leopard DVD because the version on the DVD doesn't have all the drivers the new iMac needs to run from the installer disc. However, if you have another Mac you can throw the iMac into Target Disk Mode, mount its drive on the other Mac, and install Snow Leopard on the new iMac's hard drive. Boot the iMac and then run software update to get the latest version of Snow Leopard. Alternatively, clone an updated version of Snow Leopard to the iMac. I welcome the thoughts who've done this.
Note to those reading this in the future: When Apple ships the next generation of iMacs this technique is sure to fail.