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The Behind-the-Scenes Changes Found In MacOS High Sierra (arstechnica.com)
Apple officially announced macOS High Sierra at WWDC 2017 earlier this month. While the new OS doesn't feature a ton of user-visible improvements and is ultimately shaping up to be a low-key release, it does feature several behind-the-scenes changes that could help make it the most stable macOS update in years. Andrew Cunningham from Ars Technica has "browsed the dev docs and talked with Apple to get some more details of the update's foundational changes." Here are some excerpts from three key areas of the report: APFS
Like iOS 10.3, High Sierra will convert your boot drive to APFS when you first install it -- this will be true for all Macs that run High Sierra, regardless of whether they're equipped with an SSD, a spinning HDD, or a Fusion Drive setup. In the current beta installer, you're given an option to uncheck the APFS box (checked by default) before you start the install process, though that doesn't necessarily guarantee that it will survive in the final version. It's also not clear at this point if there are edge cases -- third-party SSDs, for instance -- that won't automatically be converted. But assuming that most people stick with the defaults and that most people don't crack their Macs open, most Mac users who do the upgrade are going to get the new filesystem.
HEVC and HEIF
All High Sierra Macs will pick up support for HEVC, but only very recent models will support any kind of hardware acceleration. This is important because playing HEVC streams, especially at high resolutions and bitrates, is a pretty hardware-intensive operation. HEVC playback can consume most of a CPU's processor cycles, and especially on slower dual-core laptop processors, smooth playback may be impossible altogether. Dedicated HEVC encode and decode blocks in CPUs and GPUs can handle the heavy lifting more efficiently, freeing up your CPU and greatly reducing power consumption, but HEVC's newness means that dedicated hardware isn't especially prevalent yet.
Metal 2
While both macOS and iOS still nominally support open, third-party APIs like OpenGL and OpenCL, it's clear that the company sees Metal as the way forward for graphics and GPU compute on its platforms. Apple's OpenGL support in macOS and iOS hasn't changed at all in years, and there are absolutely no signs that Apple plans to support Vulkan. But the API will enable some improvements for end users, too. People with newer GPUs should expect to benefit from some performance improvements, not just in games but in macOS itself; Apple says the entire WindowServer is now using Metal, which should improve the fluidity and consistency of transitions and animations within macOS; this can be a problem on Macs when you're pushing multiple monitors or using higher Retina scaling modes on, especially if you're using integrated graphics. Metal 2 is also the go-to API for supporting VR on macOS, something Apple is pushing in a big way with its newer iMacs and its native support for external Thunderbolt 3 GPU enclosures. Apple says that every device that supports Metal should support at least some of Metal 2's new features, but the implication there is that some older GPUs won't be able to do everything the newer ones can do.
Like iOS 10.3, High Sierra will convert your boot drive to APFS when you first install it -- this will be true for all Macs that run High Sierra, regardless of whether they're equipped with an SSD, a spinning HDD, or a Fusion Drive setup. In the current beta installer, you're given an option to uncheck the APFS box (checked by default) before you start the install process, though that doesn't necessarily guarantee that it will survive in the final version. It's also not clear at this point if there are edge cases -- third-party SSDs, for instance -- that won't automatically be converted. But assuming that most people stick with the defaults and that most people don't crack their Macs open, most Mac users who do the upgrade are going to get the new filesystem.
HEVC and HEIF
All High Sierra Macs will pick up support for HEVC, but only very recent models will support any kind of hardware acceleration. This is important because playing HEVC streams, especially at high resolutions and bitrates, is a pretty hardware-intensive operation. HEVC playback can consume most of a CPU's processor cycles, and especially on slower dual-core laptop processors, smooth playback may be impossible altogether. Dedicated HEVC encode and decode blocks in CPUs and GPUs can handle the heavy lifting more efficiently, freeing up your CPU and greatly reducing power consumption, but HEVC's newness means that dedicated hardware isn't especially prevalent yet.
Metal 2
While both macOS and iOS still nominally support open, third-party APIs like OpenGL and OpenCL, it's clear that the company sees Metal as the way forward for graphics and GPU compute on its platforms. Apple's OpenGL support in macOS and iOS hasn't changed at all in years, and there are absolutely no signs that Apple plans to support Vulkan. But the API will enable some improvements for end users, too. People with newer GPUs should expect to benefit from some performance improvements, not just in games but in macOS itself; Apple says the entire WindowServer is now using Metal, which should improve the fluidity and consistency of transitions and animations within macOS; this can be a problem on Macs when you're pushing multiple monitors or using higher Retina scaling modes on, especially if you're using integrated graphics. Metal 2 is also the go-to API for supporting VR on macOS, something Apple is pushing in a big way with its newer iMacs and its native support for external Thunderbolt 3 GPU enclosures. Apple says that every device that supports Metal should support at least some of Metal 2's new features, but the implication there is that some older GPUs won't be able to do everything the newer ones can do.
It seems like every other update of MacOS and Xcode break something big. I'm even thinking of migrating to a VB-based Hackintosh for my Mac needs just to be able to rollback bad updates.
I'm excited about the new file system. I've corrupted HFS so many times.. But I'm gonna wait several months until the critical bugs are sorted out before I go there.
I'll say, as a game developer that has written a) OpenGL, b) Metal, and c) Vulkan renderers, I have no problems with Metal.
A year since "release" and Vulkan is still half baked - we're up to sub point release FIFTY ONE. Sit down and write the basic Vulkan code required to just cope with the swapchain and get back to me. In 2 weeks. It will make you self harm.
Metal is actually quite nice. They've hit a nice level of exposing power vs not making you have to fuck with every bloody register setting in the driver. The main problem is the Obj-C interface. Doing profiling and seeing how much time is eaten by obj_msgsend() will make you sad for a "high performance" API. But taking some time and making C++ shadow classes for some of this mitigates it.
It's now a year since Google featured Vulkan at IO and the Android situation is the typical cluster fuck. We've done the work, but have no intention of shipping until Qualcomm (Adreno) and the Mali people make drivers that aren't hot garbage.
Not an apple fanboy by any stretch (Want me to rant about xCode? Got a free week?) but uninformed people should stop constantly pushing for Vulkan without appreciating what a mess it is - especially on mobile. It will probably get there -- enough people are invested to make it happen. But it's not there yet.
We're only a 15 months past initial release, and the extension fiasco that is OpenGL is starting in Vulkan...
And what exactly are the advantages of Vulcan over Metal? No, really... serious question. Because just about every time I've seen an argument for Vulkan vs. Metal it's been all ideological purity, not technological superiority.
Does Vulkan have features that are missing in Metal (And Metal 2)? Is the performance better? Do they control patents that are being denied to Apple? If I don't care so much about free software, the GPL, and all that, but want to be able to use the better product, what's the BFD?
Imagine all the people...
They've already deployed APFS for all iOS devices. These are a nice place for FS testing, because they all tend to have regular backups and they have a debug interface that connects to Apple-controlled software for collecting problem reports. On top of that, the macOS beta testers probably include a lot of people who do weird things with their FS. I still wouldn't entirely trust it on release (the general rule of thumb is that it takes 10 years for a new FS to become stable), but it's probably had a better stress test than any other new FS. I'd be interested to know if more data is stored on APFS or ZFS at this point.
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