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The “ARM world” is almost inconceivably varied by x86 standards. There’s not even an agreed-upon boot procedure (the Raspberrry Pi’s CPU famously gets booted by

by qubex 6y ago

The “ARM world” is almost inconceivably varied by x86 standards. There’s not even an agreed-upon boot procedure (the Raspberrry Pi’s CPU famously gets booted by the GPU). Efforts to standardise this in the server space are only just getting off the ground with the Arm Server Base Boot Requirements version 1.2 being ratified last year. I doubt you’ll find Apple subscribing to anything that they won’t develop in-house. This is, after all, the company that developed the Lightening connector and sticks on its iPhones to it despite the whole industry shifting to USB-C. Basically the OS situation on Macs post-ARM is probably going to look like the Linux situation on iDevices currently: occasionally somebody manages to text-mode-boot an iPhone 7 into a profoundly unstable hacked-up kernel and there is much merriment and rejoicing, but really... macs are going to become rather exotic (on the inside). Have you ever wondered about your iPad’s boot sequence? Because you’ve never had to think about it. Notice how you can’t install versions of i(Pad)OS that are no longer signed? You think Apple will allow booting unsigned images? And all the Secure Enclave infrastructure they’ve built up? Nah.

viro 6y ago
in all fairness the Lightening connector has been around a lot longer than usb-c
- larkost 6y ago
  Beyond that, you have to acknowledge that Apple contributed heavily to USB-C. They are invested, but had to weigh the plusses and minuses of transitioning the iPhone. My guess is that it was something like this: Plusses: - everyone shares the same connectors Minuses: - all the old peripherals out there now don't work on the new phones - there are lots of debug systems for phones built into the Lightning ports that Apple uses internally, those are all gone - there are lots of junk chargers out there, and no real inspection scheme for USB-C, whereas Apple runs an inspection scheme already for Lighting Since there is a large enough market for Apple products, Apple is not worried about the small bonus of everyone sharing the same connectors. Given that it seem pretty obvious that until there is something to push them off Lightening (e.g. power requirements, speed of connection, etc...), they will stay there.
morpheuskafka 6y ago
The CPU booted by GPU is actually very similar to the way that the T2 boots the Intel CPU in existing Macs, providing signature assurance on the microcode, ME firmware, and boot image before the CPU even loads.
Dunedan 6y ago
> This is, after all, the company that developed the Lightening connector and sticks on its iPhones to it despite the whole industry shifting to USB-C. There is a rumor that Apple developed USB-C and donated it to the USB-IF [1]. Apple was also one of the first users of USB-C when they introduced the 12" MacBook in 2015. Since then they've continuously grown their adoption of USB-C, first in the MacBook Pro in 2016, then in the iMac and iMac Pro in 2017, the iPad Pro, MacBook Air and Mac Mini in 2018 and most recently in the Mac Pro in 2019. In fact nowadays the only Apple devices still not featuring USB-C are the iPhone and the (non-Pro) iPads. There are probably good reasons why Apple hasn't replaced Lightning with USB-C for the iPhone and iPad yet. If they replace Lightning with USB-C now, the whole 3rd-party accessory ecosystem has to adapt to that. While that's probably fine, if the rumors are true that Apple plans to remove all physical ports from iPhones [2] next year, that would result in USB-C equipped iPhones/iPads only being sold for 2-3 years, before there is another interface again. So Apples thinking is probably that it's more customer friendly to stick to Lightning until they replace it with a wireless solution and I'd agree with such an assessment. [1]: https://www.macrumors.com/2015/03/13/apple-invents-usb-c/ https://www.macrumors.com/2015/03/13/apple-invents-usb-c/ [2]: https://www.macrumors.com/2019/12/05/kuo-iphone-without-lightning-connector-2021/ https://www.macrumors.com/2019/12/05/kuo-iphone-without-ligh...
- qubex 6y ago
  Regarding USB-C I agree with you entirely and think you entirely missed the point I was trying to make. I am well aware Apple participated in the USB-C connector specification processes and only introduced the Lightening port when it became clear to it that USB-C would take longer to define than their urgency to ditch the old iPod 30-pin connector would allow, forcing them to ‘defect’. They’re probably rather sour about this deep down (since it forces them to have different “one size fits all” interfaces on different lines of products, which kind of undermines its own point). At any rate, the thought I was trying to express is that I would be very surprised if Apple adopted any kind of ‘standard’ ARM architecture from upon which to begin its new era of ARM-based Macs. They’re not even calling them ARM-based, they’re using the term “Apple Silicon” (which is only a marketing gimmick but it’s pretty indicative). So... they might, during the course of their preliminary analyses and feasibility studies identified a pre-existing ARM system architecture that they are comfortable with, but most likely they’ll go for something unashamedly homegrown such as whatever architecture they developed for the iPhone and iPad and consequentially whatever boot procedure they follow, which as far as I know is undocumented and subject to change (though it is the regular target of reverse-engineering, because of jail-breaking... and that game of cat-and-mouse has probably greatly enhanced code quality and reduced exposed surface area). The end result is that “from the inside” from a very low level (the kinds of hardware levels) that matters when booting an OS and that it subsequently screens userland and the users from, these details matter, and I don’t expect them to be standard, I don’t expect them to be clear, and I expect that unsigned OS images won’t be bootable. That said I read that Apple has had a session at the WWDC 2020 about booting other OSes from external drives on the ARM Developer Transition system, so who knows, I could be wrong.

by qubex 6y ago

viro 6y ago

in all fairness the Lightening connector has been around a lot longer than usb-c

larkost 6y ago
Beyond that, you have to acknowledge that Apple contributed heavily to USB-C. They are invested, but had to weigh the plusses and minuses of transitioning the iPhone. My guess is that it was something like this: Plusses: - everyone shares the same connectors Minuses: - all the old peripherals out there now don't work on the new phones - there are lots of debug systems for phones built into the Lightning ports that Apple uses internally, those are all gone - there are lots of junk chargers out there, and no real inspection scheme for USB-C, whereas Apple runs an inspection scheme already for Lighting Since there is a large enough market for Apple products, Apple is not worried about the small bonus of everyone sharing the same connectors. Given that it seem pretty obvious that until there is something to push them off Lightening (e.g. power requirements, speed of connection, etc...), they will stay there.

morpheuskafka 6y ago

The CPU booted by GPU is actually very similar to the way that the T2 boots the Intel CPU in existing Macs, providing signature assurance on the microcode, ME firmware, and boot image before the CPU even loads.

Dunedan 6y ago

> This is, after all, the company that developed the Lightening connector and sticks on its iPhones to it despite the whole industry shifting to USB-C. There is a rumor that Apple developed USB-C and donated it to the USB-IF [1]. Apple was also one of the first users of USB-C when they introduced the 12" MacBook in 2015. Since then they've continuously grown their adoption of USB-C, first in the MacBook Pro in 2016, then in the iMac and iMac Pro in 2017, the iPad Pro, MacBook Air and Mac Mini in 2018 and most recently in the Mac Pro in 2019. In fact nowadays the only Apple devices still not featuring USB-C are the iPhone and the (non-Pro) iPads. There are probably good reasons why Apple hasn't replaced Lightning with USB-C for the iPhone and iPad yet. If they replace Lightning with USB-C now, the whole 3rd-party accessory ecosystem has to adapt to that. While that's probably fine, if the rumors are true that Apple plans to remove all physical ports from iPhones [2] next year, that would result in USB-C equipped iPhones/iPads only being sold for 2-3 years, before there is another interface again. So Apples thinking is probably that it's more customer friendly to stick to Lightning until they replace it with a wireless solution and I'd agree with such an assessment. [1]: https://www.macrumors.com/2015/03/13/apple-invents-usb-c/ https://www.macrumors.com/2015/03/13/apple-invents-usb-c/ [2]: https://www.macrumors.com/2019/12/05/kuo-iphone-without-lightning-connector-2021/ https://www.macrumors.com/2019/12/05/kuo-iphone-without-ligh...

qubex 6y ago
Regarding USB-C I agree with you entirely and think you entirely missed the point I was trying to make. I am well aware Apple participated in the USB-C connector specification processes and only introduced the Lightening port when it became clear to it that USB-C would take longer to define than their urgency to ditch the old iPod 30-pin connector would allow, forcing them to ‘defect’. They’re probably rather sour about this deep down (since it forces them to have different “one size fits all” interfaces on different lines of products, which kind of undermines its own point). At any rate, the thought I was trying to express is that I would be very surprised if Apple adopted any kind of ‘standard’ ARM architecture from upon which to begin its new era of ARM-based Macs. They’re not even calling them ARM-based, they’re using the term “Apple Silicon” (which is only a marketing gimmick but it’s pretty indicative). So... they might, during the course of their preliminary analyses and feasibility studies identified a pre-existing ARM system architecture that they are comfortable with, but most likely they’ll go for something unashamedly homegrown such as whatever architecture they developed for the iPhone and iPad and consequentially whatever boot procedure they follow, which as far as I know is undocumented and subject to change (though it is the regular target of reverse-engineering, because of jail-breaking... and that game of cat-and-mouse has probably greatly enhanced code quality and reduced exposed surface area). The end result is that “from the inside” from a very low level (the kinds of hardware levels) that matters when booting an OS and that it subsequently screens userland and the users from, these details matter, and I don’t expect them to be standard, I don’t expect them to be clear, and I expect that unsigned OS images won’t be bootable. That said I read that Apple has had a session at the WWDC 2020 about booting other OSes from external drives on the ARM Developer Transition system, so who knows, I could be wrong.