Ever wanted to run Windows NT on your vintage PowerPC Macintosh? No, me neither, but now it's possible thanks to some amazing FOSS work.

The newly-released maciNTosh project brings Windows NT version 4, the state of the art operating system circa 1996, to the iMac G3, the PowerMac G3 "Blue and White", PowerBook G3 "Lombard", and PowerMac G4 "Yikes" - the state of the art in personal RISC computing circa 1997. It's a massively impressive technological achievement that will, we suspect, polarize people into shocked amazement, or leave them asking "Huh? Why?"

From its first release, Windows NT was a multiplatform OS: alongside x86-32, it also ran on computers with DEC Alpha, MIPS, and on Apple/IBM/Motorola PowerPC processors. Aside from Intel kit, of those three RISC platforms, PowerPC was by far the most common and easy to find, thanks to the success of Apple's PowerMac machines. But as always, there was a snag, and it was a doozy.

The problem was that NT needed one specific type of firmware to run on RISC computers: specifically, firmware compliant with the ACE consortium's ARC specification. This is long gone, but not forgotten: for instance the UEFI forum's history, A Tale of Two Standards [PDF] discusses it.

As industry sage Andy Tanenbaum once said, "The great thing about standards is that there are so many to choose from." For PowerPC machines there was also another, different firmware standard: the IEEE-ratified Open Firmware. NT needed ARC firmware, but - you guessed it - Apple used Open Firmware. As a result, Windows NT for PowerPC couldn't run on Apple PowerMacs.

Until now.

When Microsoft released Windows NT 4 at the end of July 1996, it set a new benchmark for personal computer OSes. Honestly, this is not hyperbole: in fact, at the time, your humble correspondent was brought in by a leading UK computer magazine to bring some balance to its review. Windows NT had already gone through three released versions: 3.1, 3.5 and 3.51. By the last, it was an extremely solid and fast PC OS - given a high-end PC for 1995, meaning SCSI storage for a start. The snag was that it had the old Windows 3 user interface. Although NT 4 didn't deliver on most of the promises of the Microsoft's Cairo project (and Vista didn't either), it did bring the superior Windows 95 user interface to the Windows NT family, including on PowerPC… if you had a PReP or CHRP workstation. Most people didn't.

What developer Rairii - who calls himself Wack0 on Github - has done is ported a version of the PowerPC ARC firmware, plus a loader to get it into RAM, and some basic drivers to bring up keyboard, mouse, IDE and a framebuffer to certain models of Apple gear: the tray-loading iMac G3, PowerMac G3 "Blue and White", PowerBook G3 "Lombard", and PowerMac G4 "Yikes". This is a remarkable achievement: while he's taken code from several other projects, including OpenBIOS and Coreboot, this is still a hugely impressive effort.

Unfortunately, the Reg FOSS desk gave away all his kit from this era before emigrating in 2014, so we have nothing suitable to try it on. Virtually Fun's Neozeed does, and they already wrote a blog post about it, complete with screenshots - and there's some more on their Twitter X feed.

Nearly 30 years later, this is totally useless, and Microsoft dropped PowerPC support after NT 4 Service Pack 2 anyway. (NT 4 got all the way to SP 6A, after which Microsoft stopped support.) It's also reportedly very slow, but that makes it no less amazing to us. ®

https://www.theregister.com//2024/07/17/windows_nt_on_powermac_g3/