operating system. Its presence enforces a form of digital rights management, preventing Mac OS X being installed on stock PCs. The name of the kext is a reference to the Mac OS X license conditions, which allow installation on Apple hardware only. According to Apple, anything else is stealing Mac OS X. The kext is located at /System/Library/Extensions on the volume containing the operating system. The extension contains a kernel function called that performs AES decryption of "apple-protected" programs. A system lacking a proper key will not be able to run the Apple-restricted binaries, which include , , , , , , , , , or . If the check fails, a short poem is displayed, reading "Your karma check for today: There once was a user that whined, his existing OS was so blind, he'd do better to pirate an OS that ran great, but found his hardware declined. Please don't steal Mac OS! Really, that's way uncool. (C) Apple Computer, Inc." After the initial announcement of first Intel-based Mac hardware configurations, reporting a Trusted Platform Module among system components, it was believed that the TPM is responsible for handling the DRM protection. It was later proven to not be the case. The keys are actually contained within the System Management Controller, a component exclusive to Apple computers, and can be easily retrieved from it. These two 32-byte keys form a human-readable ASCII string copyrighted by Apple, establishing another possible line of legal defence against prospective clone makers. Virtualization The Intel Core Duo (and later, including the current i5, i7, i9, and Xeon) processors found in Intel Macs support Intel VT-x, which allows for high performance (near-native) virtualization that gives the user the ability to run and switch between two or more operating systems simultaneously, rather than having to dual-boot and run only one operating system at a time. The first software to take advantage of this technology was Parallels Desktop for Mac, released in June 2006. The Parallels virtualization products allow users to use installations of Windows XP and later in a virtualized mode while running OS X. VirtualBox is virtualization software from Oracle Corporation, which was released January 2007. Available for Mac OS X as well as other host operating systems, it supports Intel VT-x and can run multiple other guest operating systems, including Windows XP and later. It is available free of charge under either a