This seems to come up again and again in multiple threads so I thought I'd try and do a not-too-technical summary.
TLDNR:
An ARM Mac won't run Bootcamp in the same way that your washing machine won't run Minecraft.
Bootcamp/direct-booting/dual-boot
Bootcamp works because Intel Macs don't just have the same x86 processor architecture as a Windows PC - they pretty much are Windows PCs in terms of hardware and firmware so regular x86 Windows will run on x86 Mac hardware virtually unmodified[1].
All "Bootcamp Assistant" (to give it it's full name) does is hold your hand while you split your disk into Apple- and Windows-formatted partitions, download drivers and install the (current) version of Windows from a bog-standard Windows 10 USB stick or download.
On an ARM-based system, though, Windows 10 for x86 won't run at all (because it needs an x86) - and while there is a Windows 10 for ARM, there's no such thing as a "bog standard Windows 10 ARM USB stick" designed for users to install on generic systems: currently, Microsoft only sells it to PC makers who pre-install it on their machines.
We have pretty much zero details on what the ARM Mac's architecture is going to be like (beyond what we can guess from the iPad) so it's not even a given that Windows or ARM Linux could run directly on ARM Mac hardware. So Bootcamp on ARM would really have no purpose.
Now, Apple have said that they won't support "direct booting into other OSs" which sounds like it goes further than just Bootcamp, but bear in mind that they don't currently support direct booting into any OS other than the current version of Windows 10. Even on Intel Macs, if you want to install Linux directly then it's between you and the Linux distro makers - and if it breaks you get to keep both halves.
We've yet to see whether Apple will actively block direct booting Linux etc. - but they have said that Big Sur still lets you disable "secure boot" and install unsigned versions of MacOS so don't give up hope. If it's possible to get it to boot Linux directly then someone will probably do it. But running ARM Windows in any form will need Microsoft to specifically allow it.
However, the only reason you would need to run Windows or Linux directly is to run high-performance software or high-end games - in which case, sorry, you have 2 years to pick out a nice PC (or an XBox). For most other purposes, having to re-boot to change operating systems (and deal with reading/writing APFS from Windows or NTFS from Mac), needing fixed drive partitions, not having snapshot/revert facilities and sandboxing isn't worth the effort and virtualisation is the way to go.
Virtualisation & emulation
Let's be honest here - the language is ambiguous and "virtual machine", "emulation" all have generic meanings - but in the context of software like Parallels/VMWare/QEMU etc. we're usually talking about:
emulation: simulating an entire machine - including whatever CPU it uses - in software. This is perfectly compatible, but slow. (QEUMU/UTM on iPad, SoftPC/SoftWindows for people with longer memories[2]).
virtualisation: running several operating systems - built for the same CPU type - simultaneously, on the same CPU. (Parallels, VMWare, Apple's built-in Hypervisor kit). That includes... let's call it "simulating"... the hardware & firmware environment that each OS expects, so each OS thinks it has its own memory, disc, GPU etc. (Parallels, VMWare, VirtualBox, MacOS Hypervisor kit etc. - AKA "Hypervisor" software)
containerisation: some other time, maybe... (Docker etc.)
Under that definition, the x86 "virtualisation" that we're used to just isn't possible on an ARM Mac. What you can have is either:
(a) ARM Virtualisation - Yes, folks, ARM can do virtualisation and ARM chips have their equivalent to Intel VT-x[4], but it is for running operating systems built for ARM - including ARM Linux and (if/when Microsoft allow it to happen) ARM Windows. ARM Linux is pretty well developed these days, and if MS does play ball, Win10 Arm's built-in x86 translation will probably be the least worst way to run Win32 applications.
(b) x86 Emulation - basically back to the SoftWindows days, i.e. pretty slow - although emulation technology has improved since then. If you only need Windows to file your tax return or run some bit of 15-year-old legacy software then this would probably do the job.
(c) Something clever using Rosetta 2 technology - which really falls under the heading of "more efficient emulation".[3]
(d) Remote desktop: run x86 Windows/Linux in the cloud and access it via Remote Desktop. Someone like Parallels or MS could bundle this up as a service - there would probably be a market beyond just ARM Mac users.
Parallels etc. will have to be substantially re-written - unlike most applications they do have a lot of x86-specific elements - but Apple have actually shown Parallels running on ARM so it is clearly a priority for them. My guess (just speculation) is that it will offer at least two of (a,b,c,d) above and might "just" be front-ends for MacOS's built in Hypervisor framework rather than re-inventing the wheel.
(NB: There is already an iPad/iPhone app - that can run Windows x86 under emulation - UTM - but I wouldn't base any judgements on it
What Apple showed at WWDC was most probably (a) but could easily have been (b) or (c) - running Apache and serving the default web page is hardly heavy lifting.
Docker (etc.)
Just to clear things up (for anybody not familiar) - Docker is a Linux-only application that implements a system for building sandboxed server applications. "Docker for Windows/Mac" is a set of tools for remote management of Docker, which originally used VirtualBox (a free Parallels/VMWare equivalent) to create a Linux virtual machine on which to run Docker itself. Both MacOS and Windows now have their own built-in virtualisation frameworks, which newer versions of Docker for Win/Mac use, so making an ARM version of Docker for Mac shouldn't be a big deal (Apple have said that it is up and running).
Docker itself runs fine on ARM Linux - the wrinkle is that the images people download to build server stacks must have been built for ARM as well as x86 - but that is work already in progress, Apple or not, due to the interest in ARM servers from Amazon et. al. The Docker equivalent of a "universal binary" is already a thing and these "images" are mostly composed of open-source software (or the developer's own code) which already supports ARM, re-building images shouldn't be such a deal-breaker, given that people have 2-3 years before the supply of Intel Macs dries up.
...Also, since "Mac Docker" is basically a set of tools to remotely control an instance of Docker running in a virtual machine, it shouldn't matter that much whether the "real" Docker virtual machine is being virtualised, emulated, running on a $300 Dell box in your basement or somewhere out in Cloud (cuckoo) land.
Thoughts
1. If your Intel Mac evaporated (or became irreplaceable) overnight, these would be deal-breakers. But it isn't - you have at least 3 years to adapt. The wind is blowing towards web apps rather than Windows, virtual machines in the cloud, and remote development, anyway.
2. Apple appear to be taking the issue seriously and Tim seems to have finally got the memo that not everybody wants an iPad (if they wanted to turn Macs into giant iPads it would be much simpler and cheaper to release XCode for Linux/cloud and just stop making Macs).
3. All this defence of why the ARM switch needn't be the end of the world assumes that the new ARM Macs will offer enough benefits to justify a few sacrifices and compromises. We haven't seen the new Macs - or even their CPUs - yet. Until we do I'm giving Apple the benefit of the doubt (optimism over experience, maybe) and hoping that we'll see passively cooled MacBook Airs with current-MacBook Pro performance. MacBook Pros that don't thermally throttle or melt their own keyboards, Mac Minis with decent integrated GPUs, Mac Pros/iMacs with zillions of cores and on-die Afterburners... and at prices that are premium but not ridiculous. If the new Macs turn out to be overpriced and under-performing bits of abstract modern art with bug-ridden, dumbed down software, then it won't be worth lifting a finger to accommodate them. However, that's down to Apple, not the ARM instruction set.
4. There's a name for a computing platform that supports exactly the same workflows for ever and doesn't dare break backwards compatibility - it's "Windows PC".
5. All that said, if you're running high-performance Windows x86 software on Bootcamp and don't see that changing any year soon, you're probably stuffed.
[1] On my Mac Pro 1,1 you could stick in a bog-standard Windows XP DVD, reboot and install it just like you would on a "real" PC. Later versions of Windows and Mac hardware have broken that, but mainly by adding a few complications to the installation process.
[2] Or, for people with even longer memories, Acorn PC Emulator - yes folks, x86 Windows/DOS emulation on ARM in the late 1980s...
[3] Just speculation - but MacOS already includes a built-in virtualisation/hypervisor framework which could potentially be upgraded with Rosetta-based emulation/translation facilities.
[4] (not sure if the A12 implements them, but we haven't seen what the real Apple Silicon for Macs will be yet)
PS: “I apologize for such a long letter - I didn't have time to write a short one.” - Mark Twain
TLDNR:
An ARM Mac won't run Bootcamp in the same way that your washing machine won't run Minecraft.
Bootcamp/direct-booting/dual-boot
Bootcamp works because Intel Macs don't just have the same x86 processor architecture as a Windows PC - they pretty much are Windows PCs in terms of hardware and firmware so regular x86 Windows will run on x86 Mac hardware virtually unmodified[1].
All "Bootcamp Assistant" (to give it it's full name) does is hold your hand while you split your disk into Apple- and Windows-formatted partitions, download drivers and install the (current) version of Windows from a bog-standard Windows 10 USB stick or download.
On an ARM-based system, though, Windows 10 for x86 won't run at all (because it needs an x86) - and while there is a Windows 10 for ARM, there's no such thing as a "bog standard Windows 10 ARM USB stick" designed for users to install on generic systems: currently, Microsoft only sells it to PC makers who pre-install it on their machines.
We have pretty much zero details on what the ARM Mac's architecture is going to be like (beyond what we can guess from the iPad) so it's not even a given that Windows or ARM Linux could run directly on ARM Mac hardware. So Bootcamp on ARM would really have no purpose.
Now, Apple have said that they won't support "direct booting into other OSs" which sounds like it goes further than just Bootcamp, but bear in mind that they don't currently support direct booting into any OS other than the current version of Windows 10. Even on Intel Macs, if you want to install Linux directly then it's between you and the Linux distro makers - and if it breaks you get to keep both halves.
We've yet to see whether Apple will actively block direct booting Linux etc. - but they have said that Big Sur still lets you disable "secure boot" and install unsigned versions of MacOS so don't give up hope. If it's possible to get it to boot Linux directly then someone will probably do it. But running ARM Windows in any form will need Microsoft to specifically allow it.
However, the only reason you would need to run Windows or Linux directly is to run high-performance software or high-end games - in which case, sorry, you have 2 years to pick out a nice PC (or an XBox). For most other purposes, having to re-boot to change operating systems (and deal with reading/writing APFS from Windows or NTFS from Mac), needing fixed drive partitions, not having snapshot/revert facilities and sandboxing isn't worth the effort and virtualisation is the way to go.
Virtualisation & emulation
Let's be honest here - the language is ambiguous and "virtual machine", "emulation" all have generic meanings - but in the context of software like Parallels/VMWare/QEMU etc. we're usually talking about:
emulation: simulating an entire machine - including whatever CPU it uses - in software. This is perfectly compatible, but slow. (QEUMU/UTM on iPad, SoftPC/SoftWindows for people with longer memories[2]).
virtualisation: running several operating systems - built for the same CPU type - simultaneously, on the same CPU. (Parallels, VMWare, Apple's built-in Hypervisor kit). That includes... let's call it "simulating"... the hardware & firmware environment that each OS expects, so each OS thinks it has its own memory, disc, GPU etc. (Parallels, VMWare, VirtualBox, MacOS Hypervisor kit etc. - AKA "Hypervisor" software)
containerisation: some other time, maybe... (Docker etc.)
Under that definition, the x86 "virtualisation" that we're used to just isn't possible on an ARM Mac. What you can have is either:
(a) ARM Virtualisation - Yes, folks, ARM can do virtualisation and ARM chips have their equivalent to Intel VT-x[4], but it is for running operating systems built for ARM - including ARM Linux and (if/when Microsoft allow it to happen) ARM Windows. ARM Linux is pretty well developed these days, and if MS does play ball, Win10 Arm's built-in x86 translation will probably be the least worst way to run Win32 applications.
(b) x86 Emulation - basically back to the SoftWindows days, i.e. pretty slow - although emulation technology has improved since then. If you only need Windows to file your tax return or run some bit of 15-year-old legacy software then this would probably do the job.
(c) Something clever using Rosetta 2 technology - which really falls under the heading of "more efficient emulation".[3]
(d) Remote desktop: run x86 Windows/Linux in the cloud and access it via Remote Desktop. Someone like Parallels or MS could bundle this up as a service - there would probably be a market beyond just ARM Mac users.
Parallels etc. will have to be substantially re-written - unlike most applications they do have a lot of x86-specific elements - but Apple have actually shown Parallels running on ARM so it is clearly a priority for them. My guess (just speculation) is that it will offer at least two of (a,b,c,d) above and might "just" be front-ends for MacOS's built in Hypervisor framework rather than re-inventing the wheel.
(NB: There is already an iPad/iPhone app - that can run Windows x86 under emulation - UTM - but I wouldn't base any judgements on it
What Apple showed at WWDC was most probably (a) but could easily have been (b) or (c) - running Apache and serving the default web page is hardly heavy lifting.
Docker (etc.)
Just to clear things up (for anybody not familiar) - Docker is a Linux-only application that implements a system for building sandboxed server applications. "Docker for Windows/Mac" is a set of tools for remote management of Docker, which originally used VirtualBox (a free Parallels/VMWare equivalent) to create a Linux virtual machine on which to run Docker itself. Both MacOS and Windows now have their own built-in virtualisation frameworks, which newer versions of Docker for Win/Mac use, so making an ARM version of Docker for Mac shouldn't be a big deal (Apple have said that it is up and running).
Docker itself runs fine on ARM Linux - the wrinkle is that the images people download to build server stacks must have been built for ARM as well as x86 - but that is work already in progress, Apple or not, due to the interest in ARM servers from Amazon et. al. The Docker equivalent of a "universal binary" is already a thing and these "images" are mostly composed of open-source software (or the developer's own code) which already supports ARM, re-building images shouldn't be such a deal-breaker, given that people have 2-3 years before the supply of Intel Macs dries up.
...Also, since "Mac Docker" is basically a set of tools to remotely control an instance of Docker running in a virtual machine, it shouldn't matter that much whether the "real" Docker virtual machine is being virtualised, emulated, running on a $300 Dell box in your basement or somewhere out in Cloud (cuckoo) land.
Thoughts
1. If your Intel Mac evaporated (or became irreplaceable) overnight, these would be deal-breakers. But it isn't - you have at least 3 years to adapt. The wind is blowing towards web apps rather than Windows, virtual machines in the cloud, and remote development, anyway.
2. Apple appear to be taking the issue seriously and Tim seems to have finally got the memo that not everybody wants an iPad (if they wanted to turn Macs into giant iPads it would be much simpler and cheaper to release XCode for Linux/cloud and just stop making Macs).
3. All this defence of why the ARM switch needn't be the end of the world assumes that the new ARM Macs will offer enough benefits to justify a few sacrifices and compromises. We haven't seen the new Macs - or even their CPUs - yet. Until we do I'm giving Apple the benefit of the doubt (optimism over experience, maybe) and hoping that we'll see passively cooled MacBook Airs with current-MacBook Pro performance. MacBook Pros that don't thermally throttle or melt their own keyboards, Mac Minis with decent integrated GPUs, Mac Pros/iMacs with zillions of cores and on-die Afterburners... and at prices that are premium but not ridiculous. If the new Macs turn out to be overpriced and under-performing bits of abstract modern art with bug-ridden, dumbed down software, then it won't be worth lifting a finger to accommodate them. However, that's down to Apple, not the ARM instruction set.
4. There's a name for a computing platform that supports exactly the same workflows for ever and doesn't dare break backwards compatibility - it's "Windows PC".
5. All that said, if you're running high-performance Windows x86 software on Bootcamp and don't see that changing any year soon, you're probably stuffed.
[1] On my Mac Pro 1,1 you could stick in a bog-standard Windows XP DVD, reboot and install it just like you would on a "real" PC. Later versions of Windows and Mac hardware have broken that, but mainly by adding a few complications to the installation process.
[2] Or, for people with even longer memories, Acorn PC Emulator - yes folks, x86 Windows/DOS emulation on ARM in the late 1980s...
[3] Just speculation - but MacOS already includes a built-in virtualisation/hypervisor framework which could potentially be upgraded with Rosetta-based emulation/translation facilities.
[4] (not sure if the A12 implements them, but we haven't seen what the real Apple Silicon for Macs will be yet)
PS: “I apologize for such a long letter - I didn't have time to write a short one.” - Mark Twain
