all its products by 2020, in favor of UEFI Class 3. Operating systems An operating system that can be booted from a (U)EFI is called a (U)EFI-aware operating system, defined by (U)EFI specification. Here the term booted from a (U)EFI means directly booting the system using a (U)EFI operating system loader stored on any storage device. The default location for the operating system loader is <EFI_SYSTEM_PARTITION>/BOOT/BOOT<MACHINE_TYPE_SHORT_NAME>.EFI, where short name of the machine type can be IA32, X64, IA64, ARM or AA64. Some operating systems vendors may have their own boot loaders. They may also change the default boot location. The Linux kernel has been able to use EFI at boot time since early 2000s, using the elilo EFI boot loader or, more recently, EFI versions of GRUB. Grub+Linux also supports booting from a GUID partition table without UEFI. The distribution Ubuntu added support for UEFI Secure Boot as of version 12.10. Furthermore, the Linux kernel can be compiled with the option to run as an EFI bootloader on its own through the EFI bootstub feature. HP-UX has used (U)EFI as its boot mechanism on IA-64 systems since 2002. OpenVMS has used EFI on IA-64 since its initial evaluation release in December 2003, and for production releases since January 2005. The x86-64 port of OpenVMS also uses UEFI to boot the operating system. Apple uses EFI for its line of Intel-based Macs. Mac OS X v10.4 Tiger and Mac OS X v10.5 Leopard implement EFI v1.10 in 32-bit mode even on newer 64-bit CPUs, but full support arrived with OS X v10.8 Mountain Lion. The Itanium versions of Windows 2000 (Advanced Server Limited Edition and Datacenter Server Limited Edition) implemented EFI 1.10 in 2002. MS Windows Server 2003 for IA-64, MS Windows XP 64-bit Edition and Windows 2000 Advanced Server Limited Edition, all of which are for the Intel Itanium family of processors, implement EFI, a requirement of the platform through the DIG64 specification. Microsoft introduced UEFI for x64 Windows operating systems with Windows Vista SP1 and Windows Server 2008 however only UGA (Universal Graphic Adapter) 1.1 or Legacy BIOS INT 10h is supported; Graphics Output Protocol (GOP) is not supported. Therefore, PCs running 64-bit versions of Windows Vista SP1, Windows Vista SP2, Windows 7, Windows Server 2008 and Windows Server 2008 R2 are compatible with UEFI Class 2. 32-bit UEFI was originally not supported since vendors did not have any