Apple held their virtual WWDC2020 overnight and there were a raft of announcements.
Two of the biggest however that will affect all Mac users were the announcement of macOS 11 and Apple are making their own ARM-based CPUs for Macs.
macOS 11 Big Sur is a huge one – this will be the first ARM-native version of macOS and represents the first time in 15 years that Apple have increased the major version number in their operating system. We have had Mac OS X version 10.0 all the way through to macOS 10.15, and now with the release of ARM, it’s getting bumped to 11.
Apple using their own custom ARM-based processors in Macs however is even bigger news. First there was the shift from Motorola M68k to PowerPC CPUs in the late 90s, then the change from Classic Mac OS to Mac OS X in the early 2000s and the change from PowerPC to Intel x86 CPUs in 2006. These have been some massive changes, and I’ve dealt with the fallout of each and every one of them. In every case, Apple have had backwards compatibility for a period of time, however there is always disruption during the transition period.
Like with the transition from PowerPC to Intel, with Rosetta adding a translation layer so that the new CPUs could execute code for the outgoing architecture, Apple have Rosetta 2 which will emulate Intel x86 code on ARM CPUs. My experiences with Rosetta back in 2006 was that the performance was adequate, but not stellar. Although Apple’s ARM CPUs will reportedly have higher performance than their Intel equivalents, there will always be a hit to performance running emulated code. I’m sure that this time around the hit will be minimal, as Apple will have likely built functionality into their CPUs to aid emulation performance.
Ars Technica have some good roundups of the announcements:
macOS 11 Big Sur (which, you can see from the slug was originally assumed to be macOS 10.16)