MacBook AIR PRO 15'' EARLY 2014 820-2523, 820-2523-A, 820-2523-B Motherboard Schematic Circuit Diagram (BoardView)
MacBook AIR PRO 15'' EARLY 2014 820-2523, 820-2523-A, 820-2523-B Motherboard Schematic Circuit Diagram (BoardView)
PC Processor 16-Bit to 64-Bit Architecture Evolution
For non-PC contexts such as servers (for which IA-64 was built), the fact that the IA-64 architecture is not an extension of IA-32 but rather a new and entirely distinct architecture was OK, but the PC market has long relied on backward compatibility. Even though it is feasible to emulate IA-32 within IA-64, such emulation and support are slow.
With the door now open, AMD jumped at the chance to create AMD64, which are 64-bit extensions to IA-32 (originally known as x86-64). Intel ultimately came out with its own set of 64-bit extensions, dubbed EM64T or IA-32e mode. The Intel extensions, it turns out, are nearly identical to the AMD extensions, implying that they are software compatible. It seemed for the first time that Intel had unarguably followed AMD’s lead in the development of PC architecture.
On previous operating systems, however, AMD and Intel's 64-bit processors could only run in 32-bit mode. 64-bit operating systems and 64-bit drivers are also required to make 64-bit computing a reality. In April 2005, Microsoft released trial copies of Windows XP Professional x64 Edition (which supports AMD64 and EM64T), but 64-bit computing didn't become widespread until the introduction of Windows Vista x64 in 2007. The absence of 64-bit drivers was initially a problem, but by the time Windows 7 x64 was released in 2009, most device manufacturers were releasing both 32-bit and 64-bit drivers for almost all new devices. Linux is also available in 64-bit variants, allowing non-Windows settings to make the switch to 64-bit computing.
