macOS as iOS plus
By: Maxim Samoylenko
Tags: Apple, Mac, iOS, Macos

For years, Apple community has been speculating about the way Macs would switch to ARM chips. There have been many rumors, and Apple itself has been lately dropping hints. At this point, Macs moving from x86 Intel processors to proprietary ARM designs seems inevitable — the only questions are when it will happen, and how Apple is going to handle the switch software-wise.

The Mac future dilemma

There are many reasons why moving Macs to ARM chips would make sense for Apple. ARM seems to be the present and the future of CPU designs, and Apple is already heavily invested in it by creating a lineup of proprietary CPUs for iPhones, iPads, Watches, Apple TVs and other devices. It would be way easier and reasonable resource-wise to have all hardware products running on the same family of ARM chips, instead of maintaining Intel-based Mac that currently sticks out like a sore thumb. In addition, Intel has been struggling recently with producing more powerful and efficient designs, which arguably caused the slowdown of Mac hardware upgrades over the years — if Apple wants to remain an integrated company that controls all the key components of their products instead of relying on third-party vendors, moving to own chip designs for Macs would seem like a logical move.

There are also many questions. Macs have been around for decades, and there is a big and ever-growing list of software products that are written for current macOS and x86 architecture. Porting an entire operating system to another chip architecture would be a huge hassle and would surely break lots of legacy workflows and software compatibility. Is it worth it, especially considering that, with the growth of iOS and mobile form factors, Macs are increasingly becoming a niche professional use cases machines, and the last thing their users would want would be workflow and software disruptions? In addition, due to x86 compatibility, Macs are great Windows machines — moving to ARM would no longer allow Mac customers to install Windows as the second operating system on their devices.

Apple is currently facing a dilemma about the future of the Mac. Option number 1 would be to focus nearly all resources on mobile devices and wearables, have the Mac stay in its comfort zone and run its course as increasingly niche, x86-based machines until their days are numbered — or even let this market segment (not very profitable, compared to mass consumer devices market) go to competitors such as Microsoft. Option number 2 would be to reinvent the Mac and bring the platform forward by redesigning it for more niche, professional use cases, while based on modern hardware architecture — with inevitable disruptions and growing pains in the process. The second option seems very risky, especially given the age of the platform and associated behavioral debt — but it increasingly feels that this is exactly the option Apple has chosen.

In addition to rumors about Apple’s potential hardware decisions for future Macs, at last year’s WWDC, Apple announced the project to make UIKit-based apps (basically, apps for iOS) to be compatible with macOS. This project, unofficially known as “Marzipan”, has caused another wave of discussions on Twitter a few days ago, and one particular response by Jason Snell attracted my attention:

Think of macOS as iOS plus.

macOS -> terminal access, any software downloadable, supports AppKit apps, supports unified (UIKit) platform apps

iOS -> only App Store apps, only UIKit apps

I think this tweet is a very elegant description of the thinking Apple has about the future of macOS and ARM-based Macs.

From Mac OS X forks to iOS forks

As of today, Apple core OS ecosystem is a world of Mac OS / OS X / macOS forks. Modern macOS started in 2005 with Intel-based, x86 Mac OS X Tiger and then evolved into macOS that runs our Intel-powered Mac hardware we know and love today*.

In 2007, Apple shocked the world by announcing that the iPhone would run a version (a fork) of OS X, that would share the same kernel and foundations with the desktop OS. However, since iPhone has been running on ARM-based chip from day one, the iPhone OS (later known as iOS) had to be designed for ARM architecture — thus, even though technically macOS and iOS have many things in common, these are still two very different operating systems.

Fascinated by iOS and ARM capabilities, Apple then moved own to expand its family of core operating systems by introducing first watchOS, and then tvOS in 2015, both being forks of iOS. iOS, watchOS and tvOS architecturally are similar, and app development for all of them simultaneously is relatively easy — while macOS remains a somewhat black sheep of the family. It gets increasingly challenging for Apple to maintain both macOS and different iOS forks, and develop them evenly and in a lockstep. It took Apple years to bring apps like News, Home, Stocks, and Voice Memos to macOS, and they only could do this after they introduced “Marzipan”.

Faced by the challenges mentioned above, and also the willingness to move Macs to ARM chips, what could Apple do? My assumption is — Apple would retire the current x86-based macOS and would replace it with yet another iOS fork. However this time, instead of tailoring iOS to tiny wearables, or TV screens, the company would scale it up to address more complex, stationary/desktop workflows.

Essentially, a fork of iOS would be designed to replace the current macOS. It would be tasked with addressing use cases which are too niche for more mainstream, mobile-focused iPhone and iPad iOS. Perhaps, Apple would even slowly move iPad to this new iOS-based macOS, making iPads closer to MacBooks than ever. This new macOS would be based on modern architecture, would get rid of years of legacy code, would fit well with the growing demand for always-connected PCs — and of course, would be designed from the ground-up for ARM chips.

What would make the new macOS different from iOS then? As Jason Snell points out, macOS would essentially be an iOS plus. In addition to natively supporting touch-based UI and UIKit iOS apps, macOS would also allow pointer-based UI (think mouse and touchpad), multi-windowed UI, and maybe even some kind of backwards compatibility support for legacy AppKit apps.

If this assumption is correct, we would move from the world of Mac OS X forks to the world of iOS forks across all Apple hardware devices. This would allow Apple to integrate all of their operating systems even closer, maintain and update them simultaneously way more efficiently, and of course, bring Mac devices to ARM chips.

From simple to complex

Having iOS and macOS so similar and both running on ARM chips could also potentially enable Apple to work on completely new and fascinating hardware device form factors. For example, iOS and iPad Pro already supports external displays, while MacBooks are increasingly moving to touch keyboards (I believe Touch Bar to be the first step in this direction and argued it in a previous piece). At some point, there could be a device running new macOS, that would essentially be two touch displays, a horizontal one and a vertical one. A horizontal touch surface would act as the primary touch input (full touch keyboard, a trackpad, and an iPad-like UI where you touch something that you look at), while a vertical touch surface would be a display that would be primarily designed to be looked at with just occasional touch for swiping or resizing. This is not entirely my crazy imagination — Apple has already patented similar design.

You might think that this hybrid approach sounds way too similar to what Microsoft has been doing lately with their “One Windows” and ongoing quest to make Windows OS relevant in a post-PC, mobile world. Indeed, instead of developing desktop Windows and Windows Mobile/Phone OS in parallel, at some point Microsoft decided to focus on just one core OS, scale down its Windows PC OS and tailor it to mobile form factors. The success has been somewhat limited so far — Windows Phone is dead, and while Microsoft Surface is a popular product for enterprise and certain professional use cases, as a consumer tablet, it is arguably still way too cluttered and compromised. Microsoft is now also developing an ARM fork of Windows, and it remains to be seen how well it would fit the workflows of legacy x86 Windows users**.

Microsoft’s and Apple’s approaches seem to be completely different. Having their expertise and core leverage in the professional PC world, Microsoft tries to shoehorn legacy Windows into more mobile, more consumer-friendly devices, with limited success. Apple, on the other hand, would scale up their modern, future-proof, and mobile-friendly operating system to make it enable more professional and niche use cases. Innovation usually scales up and grows from simple to complex, not strips down from complex to simple — Apple seems to be playing by this rule book yet again.

There are, of course, still so many questions unanswered. When will this move happen — should we wait for rumored 2020, or will we already see the first iOS-based version of macOS at 2019’s WWDC? What will be backwards-compatible with the “old” macOS? What about AppKit apps? What about software distribution model (App Store only, or not)? What about low-level access to the system (command line, etc)? What about dual boot to Windows? Which OS would run the iPad Pro? Will ARM chips be powerful enough to run desktops such as the Mac Pro — and if not, how will Apple deal with it?

It’s only a matter of time until we hear the answers. What seems increasingly likely, however, is that Apple is moving ahead at full speed to completely reimagined macOS, not afraid of leaving its comfort zone. Buckle up, the ride is going to be bumpy, but very exciting.

* Obviously, Mac OS X previously ran on Power PC chips, and Mac OS has a rich history that predates Mac OS X

** ARM Windows, however, could potentially enable ARM Macs to still dual-boot into Windows, which would be a plus for Apple and Mac customers.