Almost every developer I have worked with considers NT and XNU to be hybrid at this point. Unfortunately, almost everything in the parent comment is incorrect.
>Mach, the microkernel, is not using in OS X and never has been.
The version of mach present in XNU is derived from OSFMK, which derives code from UoU's Mach 4 kernel, and from CMU's Mach 3 kernel. It contains improvements related to threading and contexts. It also definitely exists as more than an API. The code that makes up mach is present and identifiable, and thus is "in" XNU. [1]
>Mach, the API, is used (mostly due to legacy reasons).
See above. Abstractions are exposed, and traps are present, but this is not an API clone, it is mach, albeit modified from the original form. It was specifically chosen for its forward thinking benefits. Mach was not the basis for any major Apple OS prior to OS X. There were no "legacy reasons" to motivate its adoption.
>OS X has a Linux-style monolithic kernel (with legacy Mach APIs in userspace).
You do tend to see different opinions on this. Some argue macOS is a hybrid kernel, because it combines elements from a microkernel (mach), a monolithic kernel (BSD), and IOKit. A single address space is shared by the components though, which leads many to call it monolithic. [2]
I vaguely remember seeing a video demonstrating a an M1 device virtualizing Windows ARM faster than it ran on Surface ARM hardware. Kind of reminds me of how an Amiga of the era could be set up to virtualize(?) Mac OS faster than contemporary hardware Mac could.
Before M1 my only exposure to ARM has been low-power SBCs and Android devices, and the experience was mediocre in the “just works” department. Poor hardware support, and a lack of proprietary software support. Performance was also lacking. Apple’s tight integration and high-end CPUs have resulted in a vastly better experience, but I want to have more options than just macOS and MacBooks. I think we’re trending in the right direction, but it’s going to be a while before (5 years IMO) before we see anything approaching competitive to the M-series chips from major market players. If Microsoft could fix their frankly horrid x86 compatibility on aarch64 devices thing would speed along nicely I think.
This reads much like the musings of some of the religious fundamentalists I grew up around in my town. They purport that their way is the mainstream or "coming/silent majority", then shame anyone who falls outside their sexist and dehumanizing beliefs. They seek to make those people feel small and outcasted, thereby fulfilling their false beliefs in their own eyes. It's sad that someone could write something as sexist as she has, and not have even a shred of self-awareness about the irony of it.
The unified architecture, combined with the speed of the modules (4266 MHz LPDDR4X), combined with the close physical proximity to the CPU cores likely all contribute to the M1's memory performance.
In Apple's own words:
“M1 also features our unified memory architecture, or UMA. M1 unifies its high‑bandwidth, low‑latency memory into a single pool within a custom package. As a result, all of the technologies in the SoC can access the same data without copying it between multiple pools of memory. This dramatically improves performance and power efficiency." [0]
Part of me thinks they may intend to get rid of the physical ports altogether on the iPhone. This would serve to differentiate the "productive" iPad from iPhone, and allow them to scratch that minimalist itch they get every once in a while.