Good takes and bad takes on Apple Silicon

There are a lot of people out there that seem to be clinging to some weird ideas about what the Apple Silicon transition is going to look like, and what the Apple Silicon team "can do", in terms of what they can deliver.

Good Takes

First, someone who seems to "get it" pretty well, Rene Ritchie. Here are two of his very clear and informative videos about why "Apple Silicon" is not just "ARM", and what that means for the Mac going forward:

Rene Richie on YouTube:

Wrong About the Apple Silicon Mac

Why Apple Silicon Will Make Better Macs

The key takeaway here is that many of the huge advantages that Apple Silicon will bring to the Mac come from everything else that Apple will integrate into the chips, not just from using their own CPU cores. Having said that, I think there's a lot of confusion about the likely performance of those cores. More on that below.

Bad takes

I'm not going to link to blog posts, tweets, and YouTube videos of the bad takes, for two reasons. Primarily, because bagging on people who are coming at this from a position of ignorance seems kind of mean. But also, because there are so many bad takes for each of these positions,  there's no point in singling out any particular instance of them. Having said that, here are some bits of commonly "known facts" about Apple Silicon that I think are really wrong-headed, and why I think so.

Claim: ARM Macs will never be as fast as Intel Macs

You see a bunch of variations on this, from "obviously, the ARM processors will be for the low-end, but they'll continue to use Intel for the Mac Pro and the MacBook Pro", to "Obviously, the low-end Macs will transition first, and we won't see 'pro' Macs until late next year, at the earliest".

My take: You will see 'Pro' Apple Silicon Macs this year

Apple's flagship product is the MacBook Pro. It's the product that everybody wants, and also the one that a lot of people buy, especially "Pro Users", whatever that name might mean. Apple will definitely not carve out solely the low end of the Mac range for their new Apple Silicon processors, because the perception of "Apple Silicon means low-end" is not something they want to have stick to the new product line. 

In addition, based on what we know, and can extrapolate from, the first Apple Silicon processors are likely going to be substantially faster than the Intel processors in the existing laptop range. In single-core performance, the A12Z is already on par with the Intel processors in the MBP line. It's really hard to say what the performance improvement will be from the A12Z to the first Apple Silicon Mac chip, but my best guess is somewhere between 50% and 100% improvement over the A12Z. At that speed, those Apple Silicon chips will just wipe the floor with the current Intel processor MacBook Pros in single-core speed. Beyond that, it's mostly a question of how many "performance" cores go into that processor.

Claim: ARM Macs will not support discrete GPUs

This is apparently based on a single slide from a single WWDC 2020 presentation: Bring your Metal app to Apple Silicon Macs. Based on seeing "Intel, Nvidia, and AMD GPUs" under the Intel-based Mac heading on one side of the slide, and "Apple GPU" on the other side, under Apple Silicon, some people have apparently concluded that discrete GPU support is not going to be available on Apple Silicon.

My Take: We really don't know, but it seems unlikely that discrete GPUs will never be supported

The point of the presentation at WWDC was very much not "we won't support discrete GPUs on Apple Silicon". The point of the presentation was "you definitely don't want to assume that 'integrated equals slow', when dealing with Apple Silicon". It's likely that Apple will still have discrete GPU options on some of their Pro devices.

However, I would not be at all surprised if the first few Macs released didn't have discrete GPUs, because the integrated GPU will have better performance than the top laptop GPUs currently available. We do know that Apple Silicon Macs will have Thunderbolt and PCIe, so they will have the hardware capability to support discrete GPU configurations, including external GPUs. It's just a question of drivers, at that point. Apple will either write the needed drivers, or pay the GPU vendor to write them, if they're needed to achieve a particular performance level.

Claim: Much existing software will not come to Apple Silicon Macs soon, or indeed at all

This is often tied to the argument that "x86 processors are just better for 'heavy processing' than ARM, which are optimized for power efficiency". Given that assumption, they then say you won't see Photoshop, or Logic, or Premiere, or whatever other piece of software on ARM Macs, because they won't be fast enough. A different argument is that the effort of porting will be too high, and so third-party developers will not bother porting to the Apple Silicon architecture.

My Take: Building for Apple Silicon is pretty darn easy, and Rosetta2 is better than you think

I talked about this in a previous post, but this transition is going to be much less painful for most developers than the PPC->Intel transition was, or in fact than the transition from x86-32bit to x86-64, which a bunch of developers just went through for Catalina. If an app runs on Catalina, it'll run on Apple Silicon, eventually.

I need to be careful about what I say in this next section, because I do have the Apple DTK, and it came with a fairly restrictive NDA, saying not to talk about performance or benchmark results. But I have run a bunch of third-party software under Rosetta2, and other than a compatibility issue related to page size that's described in the DTK release notes (you may not be able to read that, without a developer account), almost everything I've tried runs perfectly well. It's actually hard to tell the difference between running under Rosetta, and running something native. It does use more CPU power to run a Rosetta process than a native process, and they're slow to start the very first time, but other than that, it's completely seamless.

Someone posted Geekbench scores from a DTK, with Geekbench running under Rosetta, and the performance is 20-30% slower than native (as compared to the iPad Pro running the iOS version natively). Assuming that holds generally, and that the Apple Silicon Mac processors will be substantially faster than the existing Intel Mac processors, I wouldn't be too surprised if for many users, running their existing software under Rosetta would still be a performance improvement over their current Mac. Once native versions of these apps become available, there will be no contest.

Claim: The Surface Pro shows that ARM isn't ready for the desktop

The Surface Pro is an obvious comparison to make, because it's an "ARM laptop", running an ARM version of Windows. They're great, for what they are. But they haven't been a great success. The lack of software support, and disappointing performance when emulating x86 code, has been used to justify skepticism of the viability of Apple Silicon Macs.

My Take: The Surface Pro is a great example of the key differences between Apple and Microsoft.

From a third-party developer's perspective ARM Windows is this weird off-shoot of the main Windows product line. Even if you want to support it, it's a much smaller market than the x86 mainstream Windows family, and so the payoff for the porting work is uncertain. When Apple switches to Apple Silicon, they will completely switch over. At the end of the two year transition, every new Mac will be running on Apple Silicon. If you want to be in the Mac software market, you will need to support Apple Silicon.

It turns out that there is hardware support for Total Store Ordering, or TSO, built in to Apple Silicon processors. This was somehow discovered by a third party, and they've subsequently released a proof-of-concept for enabling TSO on a per-thread basis on the DTK. The relevance here is that TSO is one of the major differences between the memory model of Intel processors and ARM processors. By providing this switch, Apple have eliminated a huge source of synchronization slowdowns (and potentially bugs) when translating x86 code to ARM code in Rosetta. This is a hardware feature implemented just to support a particular piece of software, and a great illustration of the advantages Apple gets from controlling the entire stack from hardware to applications.

Claim: Geekbench is not a realistic benchmark, and doesn't reflect real-world performance

This is a fun one. Since Geekbench shows the A12Z as being on par with current Intel laptop chips, it must be that the benchmark is wrong, or intentionally skewed in Apple's favor.

My Take: Benchmarking is hard, but Geekbench is at least trying to be fair

You can see descriptions of the Geekbench micro-benchmarks here and here. There's nothing in here that would obviously bias these tests towards or away from any particular processor. They're artificial benchmarks, but are built up of things that real applications actually do - image compression, database operations, etc, etc.

Conclusion

The first round of Apple Silicon Macs are going to be setting the conversation for the next year about the wisdom of Apple's rather risky decision to abandon Intel. Apple obviously knows this, and I would not be at all surprised if the first Apple Silicon MacBook Pro (or whatever they call the pro laptop, if they rename it) will be the fastest Mac laptop yet. And the desktop Macs will also be an impressive upgrade over their current counterparts.

ARM Macs are coming, and faster than you think

ARM Macs and transition timeframes

(note: This is a lightly-edited version of a post originally published on June 13th, 2020)

We all knew this was coming. In fact, some of us have been expecting it for years. Various rumor outlets are saying that Apple will announce at WWDC that they're transitioning the Macintosh line from using Intel's processors to Apple's own processors, which are based on the ARM architecture.

A bunch of people have written extensively on this rumor, but I have a few thoughts that I haven't seen others concentrate on.

One thing you see a lot of disagreement about online is how long it'll take for Apple to convert its whole lineup of Macs to use its own processors, or if it even will. I've seen people say that they think they'll announce a single model of ARM Mac, then over the course of 2-3 years, move all of the product line over to ARM. I've even seen people predict that they'll keep the "Pro" line of computers on x86 for the foreseeable future, and only convert the portable line to ARM.

A case can be made for those positions, but here's what I think: If Apple announces a transition to ARM at WWDC, it'll happen surprisingly quickly. I wouldn't be at all surprised if the first ARM Macs ship before the end of 2020 , and the whole line is switched over before the end of 2021. That seems like a pretty far out-there prediction, compared to the "consensus" view, so let's take a look at the previous transitions, and how this one is different.

We've been here before, but then again, this is very different

This will be the third major processor transition for the Macintosh (and the 5th major software transition overall). Originally, the Mac used the Motorola m68k processor family. After 10 years, the m68k family was failing to make regular improvements in performance, and Apple started to look at other options, finally settling on the PowerPC. They moved the Mac products from m68k to PPC over the course of about 18 months. Years later, they transitioned from PowerPC to Intel, over the course of about 12 months. And now, we're apparently on the cusp of another processor transition. How will this one turn out? And most importantly: WHY NOW?

Transition 1: The m68k to PowerPC transition

"Any sufficiently-advanced technology is indistinguishable from magic"

– Arthur C. Clarke

This transition was very difficult, both for Apple and for third parties. At the time that Apple announced the change, they were still using what we now call the Classic MacOS. Large parts of the operating system, and the applications that ran on it, were written in Assembly, with an intimate understanding of the hardware they ran on.

Consequently, Apple developed a processor emulator, which would allow existing m68k code to run on the PowerPC without any changes. You could even have an application load a plugin written for the other architecture. The new PPC version of MacOS maintained a shadow copy of all its internal state in a place where 68k applications could see (and modify) it - that was the level of compatibility required to get anything to work. A heroic effort, and it paid off - most software worked out of the box, and performance was "good enough" with emulated code, because the PPC chips were much faster than the m68k chips they were replacing.

The downside of that sort of transition is that it takes many years to complete. There was relatively little pressure on the third parties to update their applications, because they ran just fine on the new models. Even the MacOS itself wasn't completely translated to native code until several years later. 

Transition 2: The MacOS X transition

“If I need to make that many changes, I might as well drop the Mac, and go to Windows”

– Some Mac developer, a Halloween party in 1999

A few years after the PPC transition, Apple announced MacOS X, and software developers were faced with another transition. Originally, OS X was intended to be a clean break with Classic MacOS, with an all-new underlying operating system, and a brand new API, Cocoa (based on the OPENSTEP software which came in with the NeXT acquisition).

Major developers were (understandably) not enthusiastic about the prospect of rewriting the majority of their existing applications. Eventually, Apple caved to the pressure, and provided Carbon, a "modern" API that kept much of the same structure, but removed some of the more egregious aspects of Classic MacOS programming. Apple made it clear that they considered Carbon a transitional technology, and they encouraged developers to use Cocoa. The reaction from the larger developers was pretty much "meh." Quite a few smaller long-time MacOS developers enthusiastically embraced the new APIs though, appreciating the productivity boost they provided.

A footnote to this chapter of the saga is that the "Developer Preview" versions of Rhapsody, the first Mac OS X releases, actually had support for running the OS on Intel-based PC hardware. That didn't survive the re-alignment which gave us Carbon, and MacOS X 10.0 shipped with support for PowerPC Macs only. 

Things were pretty quiet on the Macintosh front for a few years. New versions of OS X came out on a regular schedule, and Apple kept coming out with faster and better PowerBooks, PowerMacs, iBooks, and iMacs. And then, suddenly, the PowerPC processor line had a few unexpected hiccups in the delivery pipeline.

Transition 3:The Intel transition

“Wait, you were serious about that?”

– Carbon-using developers, overheard at WWDC 2005

The PowerPC processors were looking less and less competitive with Intel processors as time went by, which was an embarrassment for Apple, who had famously built the PowerPC advertising around how much faster their chips were than Intel's. The "G5" processor, which was much-hyped to close the gap with Intel, ran years late. It did eventually ship, in a form that required liquid cooling to effectively compete with mainstream Intel desktop PCs. The Mac laptop range particularly suffered, because the low-power laptop chips from Motorola just...never actually appeared.

And so, Apple announced that they were transitioning to Intel processors at WWDC 2005. I was working in the Xcode labs that year, helping third-party developers to get their code up and running on Intel systems. I worked a lot of "extra shifts", but it was amazing to see developers go from utterly freaked out, to mostly reassured by the end of the week.

For any individual developer, the amount of “pain” involved in the transition was variable. If they’d “kept up with” Apple’s developer tools strategy in the years since the introduction of Mac OS X, no problem! For the smaller indie developers who had embraced Xcode, Cocoa, and all of Apple's other newer framework technology, it actually was a trivial process (with one exception). They came into the lab, clicked a button in Xcode, fixed a bunch of compiler warnings and errors, and walked away with a working application, often in just an hour or so. 

For the developers with large Carbon-based applications built using the Metrowerks compiler, it was a real slog. Because of CodeWarrior-specific compiler extensions they'd used, different project structures, etc, etc,  it was hard to even get their programs to build in Xcode.

The exception to the "it just works" result for the up-to-date projects is any kind of external I/O. Code that read or wrote to binary files, or communicated over a network, would often need extensive changes to flip the "endianness" of various memory structures. Endianness is something you generally don’t need to think about as a developer in a high-level language, especially if you're only developing for one platform, which also just happens to use the same endianness as the Internet does. Luckily, these changes tended to be localized.

Transition 4: The 64-bit transition

“You can't say we didn't tell you this was coming..."

– Some Apple Developer Tools representative (probably Matthew), at WWDC 2018

The first Intel-based Macs used processors that could only run in 32-bit mode. This is what I consider one of Apple's major technology mistakes, ever. They should have gone directly to 64-bit Intel from the get-go, though that would have required waiting for the Core II Duo processors from Intel, or using AMD chips, or doing the iMac first, and the notebooks last.

Regardless, after the first year, all Macs were built with 64-bit capable processors, and MacOS started supporting 64-bit applications soon after. Technically, the previous versions of Mac OS X supported 64-bit applications on the "G5" processors, but that was only available in the Power Mac G5, and very few applications (other than ports from workstation hardware) bothered to support 64-bit mode.

Unfortunately for the folks hoping to see a glorious 64-bit future, there was again very little incentive for developers to adopt 64-bit code on MacOS. One of the advantages of Intel-based Macs over the PowerPC versions is that you could reuse code libraries that had been written for Windows PCs. But, of course - almost all Windows applications are written for 32-bit mode, so any code you share between the Windows and Mac versions of your application need to be 32-bit. You also can't mix-and-match 32-bit and 64-bit code in the same process on MacOS. So most MacOS applications remained 32-bit for years after there were no longer any 32-bit processor Macs being sold. Even when OS X 10.7 dropped support for 32-bit processors entirely, most applications stayed 32-bit.

Apple told  developers at every WWDC from probably 2006 on  that they should really convert to 64-bit. They'd talk about faster performance, lower memory overhead for the system software, and various other supposed advantages. And every year, there just didn’t seem to be any great need to do so, so mustly, all Mac software remained 32-bit. A few new APIs were added to MacOS which only worked in 64-bit applications, which just had the unfortunate effect of those features never seeing wide adoption.

Eventually, Apple's tactics on this issue evolved from promises to threats and shaming. Developers were told at WWDC that 32-bit applications would not be supported "without compromises" in High Sierra. Then, when High Sierra shipped, we found that Apple had added a warning message that 32-bit applications were "not optimized" for the new OS. That got the end users to start asking developers about when they were going to “optimize” for the new operating system. For the better part of a year, many developers scrambled to get their apps converted before MacOS Mojave shipped, because they made the reasonable assumption that the warning message was implying that Mojave wouldn’t support 32-bit applications. But then Mojave shipped, and 32-bit apps ran the same as they ever have, with the same warning that was displayed in High Sierra. And then, in MacOS Catalina, they finally stopped allowing 32-bit software to run at all.

Converting an existing 32-bit Cocoa application to 64-bit is not particularly difficult, but it is...tedious. You end up having to make lots of small changes all over your code. In one project that I helped convert, there were changes needed in hundreds of source code files. We got there, but nobody thought it was fun, and it seemed so pointless. Why inflict this pain on users and developers, for what seemed like no gain?

You couldn't say that we weren’t warned that this was coming, since Apple had been telling developers  for literally a decade to convert to 64-bit. But third-party developers were still pretty confused about the timing. Why "suddenly" deprecate 32-bit apps for Catalina? Just to incrementally reduce the amount of maintenance work they needed to do on MacOS? Or to reduce the amount of system overhead by a handful of megabytes on and 8GB Mac? It didn’t make sense. And why did they strongly imply it was coming in Mojave, then suddenly give us a reprieve to Catalina?

Transition 5: The ARM Mac

“The good news is, you've already done the hard part”

– Apple, WWDC 2020

With all of this in mind,  I think that the sudden hard push for 64-bit in High Sierra and beyond was a stealth effort to get the MacOS third-party developers ready for the coming ARM transition. When High Sierra shipped, almost all MacOS software was 32-bit. Now that Catalina is out, almost all the major applications have already transitioned to 64-bit. Perhaps the reason the “deadline” was moved from Mojave to Catalina was because not enough of the “top ten” applications had been converted, yet?

Prior to finally getting all third-party developers to adopt 64-bit, the transition story for converting to ARM would have been complicated, because the applications were all 33-bit, and the Mac ARM chips would be 64-bit (the iOS platform having had their 64-bit conversion a few years back). Apple would have been telling developers: "First, you need to convert to 64-bit. Then, you can make any changes needed to get your code running on ARM".

Now, it's going to be very simple: "If your application currently builds for Catalina, with the current SDK, you can simply flip a switch in Xcode, and it'll be able to run on the new ARM Macs, as well". That's not going to be literally true for many applications, for various reasons (binary dependencies on some other third-party SDK, Intel-specific intrinsics in performance-critical code, etc). 

But this time, there is no endianness issue, no apps that will need to change their toolchain, none of the previous issues will be relevant. I also think it's quite likely that there will be very few arbitrary API deprecations in MacOS 10.16, specifically to make this transition as painless as possible for as many developers as possible.

What’s it all mean, then?

"All of these products are available TODAY"

– Steve Jobs's famous tagline, possibly heard again this year?

So then - on to timing. For the Intel transition, there were about 6 months between announcement and availability of the first Intel Mac, and another 8 months before the transition was complete. This time, it's likely that Apple will shrink the time between announcement and availability, because there's comparatively little work that needs to be done to get most applications up and running on the new hardware.

It's possible that they'll announce ARM Macs, shipping that very day. If Adobe and Microsoft are already ready to go on day one, it might even be plausible. I think they'll want to give developers some time to get ready, though. So, I predict 3 months, meaning ARM Macs in September, 2020. And I think they'll move aggressively to put as many Macs on their own processors as they can, because it's all a win for them - lower costs, better battery life, etc, etc.

"But what about the Mac Pro?", you'll hear from some experts. "Nobody's ever produced a Xeon-equivalent performance ARM chip. It'll take years to make such a design, if it's even possible at all".

The obvious comeback here is: Nobody knows what Apple has running in a lab somewhere, except the people who are working on the project. Maybe they already have an 80 Watt ARM powerhouse chip running in a Mac Pro chassis, right now. But even if they don't, I think it's reasonable to look at this from the "Why Now?" perspective, again.

The previous processor transitions were mainly driven by a need to stay competitive in performance with Intel. That is not the case this time, since the desktop/laptop competition is almost exclusively on the same Intel processors that Apple is using. The success, or rather the lack thereof, of other ARM-architecture computers & operating systems (Windows for ARM, ChromeBooks) doesn't make a compelling case for a switch to “keep up” with Microsoft or Google, either. So there's no hurry.

Given that there's no external pressure to switch, Apple must think that they have a compelling story for why they're switching. And that has to include the entire product line, since the Mac isn't their most-important product, and they surely aren't going to support two different architectures on it, just to keep existing Mac Pro users happy. They either have a prototype of this Mac Pro class processor ready to go, or they're very sure that they can produce it, and they have a believable roadmap to deliver that product. Otherwise, they’d just wait until they did.

Which Macs are switching first?

“I bet you didn’t see that coming, skeptics!”.

– Me, maybe?

Everybody is expecting to see a new Macbook, possibly bringing back the 12-inch, fanless form factor, and taking maximum advantage of the power-saving and cooler operation of Apple’s own chips. Some folks are expecting a couple of different models of laptops.

What I would really love to see (but don’t much expect) is for Tim Cook to walk out on stage, announce the first ARM-based Mac, and have it not be a super-small, low-power consumer laptop product. I want it to be  something high end that decisively outperforms the current Mac Pro, and establishes that this is going to be a transition of the whole line. I think that'd be a bold statement, if they could swing it.

Obsolescence is a pain in the neck...

I'm trying to clean out some of the unused/unloved technology around the house. An interesting case that I'm currently working on is Yvette's old laptop. She used this thing back in her college days, and it'd be nice to be able to get the data off it (for nostalgic purposes), then send it to the great computer graveyard.

It's an approximately 20-year old NEC DOS-based laptop, with a black-and-white LCD screen, and a massive 20 MB hard drive. It boots and seems to run just fine, a bit of a miracle in itself, but I haven't yet figured out how to get the data off of it.

You'd think that it'd be relatively easy to copy the data off this thing, but:

1. Accessing the floppy drive causes the computer to reboot.

2. Neither the serial port nor the modem are recognized by the communications software installed on the thing, so I can't transfer data that way.

3. This computer is old enough that those (and the printer port) are only external I/O ports - there's no USB, no network port, and no wireless network ability.

I took the thing apart, and discovered that the hard drive in it is actually an IDE drive. Wow - that's almost a current-generation drive technology. I figured I could just get an adapter, and connect the old hard drive directly to a new system. Piece of cake, right? I've already got a Firewire-to-IDE external drive case, so it ought to be just a matter of hooking things up.

Not so fast. They do make a 44-pin to 40 pin adaptor just for connecting laptop 40-pin drives to an IDE connector, and I can connect that adapter to my Firewire-to-IDE external drive enclosure, and the drive spins up on power-up and everything. However, it isn't recognized properly. Apparently the firewire-IDE adapter doesn't work correctly with this drive. If I had to take a guess, I'd guess that the adapter doesn't support IDE drives which don't do DMA transfers.

It's a bit frustrating to have a drive that I know is readable, and have no way to get the data off of it. I'll probably try another IDE bridge and see if it works with this drive, but if that's a bust, I may be in the market for an OLD PC that I can connect the drive to, copy the data off of it, and then recycle.

There may be a trip to Weird Stuff Warehouse in my near future...