Launched yesterday as a developer-preview, Apple's OS X "Mountain Lion" will support fewer Macs than its predecessor, probably because of increases in hardware requirements for smooth operation that older Macs can't quite guarantee. The support list for Mountain Lion looks like this:

• iMac (mid 2007 or later)
• MacBook (13-inch Aluminum, 2008), (13-inch, plastic, Early 2009 or later)
• MacBook Pro (13-inch, Mid-2009 or later), (15-inch, 2.4/2.2 GHz), (17-inch, Late 2007 or later)
• MacBook Air (Late 2008 or later)
• Mac Mini (Early 2009 or later)
• Mac Pro (Early 2008 or later)
• Xserve (Early 2009)

As you can see, some x86 Mac models are out of the support list, including importantly, the pre-Unibody plastic Macbook Pros. Perhaps Apple will support Mac OS X "Lion" with security updates for a lot longer.

Thanks to the addition of the new Quad-core Intel Nehalem Xeon processors series 5500, the updated Xserve announced today delivers up to twice the performance of the previous system. For those not familiar with the term Xserve, this is the name of Apple's first 1U rackmount line of servers. It was first introduced in 2002, and thanks to this update now it is available with up to two 2.93 GHz Intel Xeon processors, up to 3 TB of hot-plug internal storage using various hard drive modules and up to 32 GB of 1066 MHz DDR3 ECC memory on 8 slots. Starting at $2,999, Xserve includes an unlimited client license for Mac OS X Server version 10.5 Leopard and enough power to become your file or web server. For the full tech specs, please click here.