Apple Likes to Switch CPU Architectures
When it comes to Apple CPU Architectures, they don’t play favorites. Instead of sticking to one architecture like all the other computer companies, Apple uses the one that is best for their devices use case. They also consider the era in which these devices are used.
The Motorola Days
The original macintosh used a Motorola 68000, or 68K, CPU. The design implements a 32-bit instruction set, with 32-bit registers and a 32-bit internal data bus. The address bus is 24-bits and does not use memory segmentation, which made it popular with programmers. Internally, it uses a 16-bit data arithmetic logic unit (ALU) and two more 16-bit ALUs used mostly for addresses, and has a 16-bit external data bus. For this reason, Motorola termed it a 16/32-bit processor.
The original macintosh was released in 1984 and used a Motorola 68000, or 68K, CPU. The 68K uses a 32-bit instruction set, and has 32-bit registers. It also has a 32-bit internal data bus. The address bus is 24-bits wide and has no memory segmentation. This feature made the chip popular with developers at the time. Under the hood it uses a 16-bit data ALU (Arithmetic Logic Unit) to crunch numbers. It also has two additional 16-bit ALUs that are used mostly for addresses. The Motorola 68K has a 16-bit external data bus. So it’s basically half way between a 16-bit and 32-bit processor.
Then on October 17, 1998 Apple released Mac OS 8.5, This was the first version of Mac OS that ran solely on PowerPC processors. PowerPC is RISC (Reduced Instruction Set Computer) CPU architecture that was created by the 1991 Apple–IBM–Motorola alliance. This Apple CPU architecture provided much more performance and flexibility than the old 68K chips
In 2005, Apple’s latest CPU architecture switch became public knowledge. They revealed it at the the WWDC 2005 (Worldwide Developers Conference). The Apple CEO, which was Steve Jobs at the time, told everyone that Apple was transitioning away from the use of PowerPC microprocessors. Apple’s first press release said that the transition would begin some time in June of 2006, and will be completely done by the end of 2007. It happened much faster than that, however.
The first Intel-based Macs were released in January of 2006. This was the same time that Mac OS X 10.4.4 Tiger was released.
And Now It’s Time For ARM
Apple’s switch to ARM is more than just the company finding the best CPU architecture to use, Remember, Apple is a driving force in the market in more than one way. Not only does it dictate the market, but it also predicts it.
This is basically Apple saying, ‘The ARM CPU architecture is ready for prime time.’
Related post: nVidia Bought ARM for $40 Billion Dollars