EMULATION MAKING WINDOWS ON ARM GREAT AGAIN

HOW DO THE LATEST LAPTOPS AND MACS RUN INTEL SOFTWARE ON THEIR ARM PROCESSORS? DARIEN GRAHAM-SMITH EXPLORES THE WONDERFUL WORLD OF EMULATION

Microsoft's “Copilot+ PCs” are supposed to usher in a new era of AI-assisted computing, but they're historic in another way, too. With surprisingly little fanfare, Microsoft has for the first time endorsed a range of third-party laptops based on a mixture of AMD, Intel and Arm processors.

This isn't the first time the firm has offered a version of Windows that runs on the Arm architecture, but it might be the first time the idea succeeds - because the OS now includes an emulation layer. Conceptually this is much the same as the clever software tools that let you tinker with a virtual BBC Micro inside a web page, or revisit old Amiga games on your phone. In this case, though, it's designed not for historical purposes, but to allow the latest Intel-native apps to run on the Arm hardware.

It's a similar approach to what Apple did with the launch of its M-series processors (see p43), and it promises the best of all worlds, combining Windows' huge existing software library with the efficiency and battery life of Arm. If you're curious as to how we've got here, and what emulation could mean for your next laptop, read on.

NO EMULATION, PLEASE – WE'RE WINDOWS

Microsoft has a long history of developing Windows for multiple different hardware platforms. In the 1990s you could buy versions of Windows NT not only for the familiar Intel x86 platform, but also for rival workstation and server systems such as PowerPC, DEC Alpha and MIPS - each with its own proprietary instruction set architecture (ISA). In the early 2000s, support was added for Intel's 64-bit Itanium platform too.