Classic MacOS for non-Apple PowerPC kit rediscovered
Beyond the Mac clones, there were PC-style PowerPC machines, and a version of classic MacOS for them has just been rediscovered, opening up new possibilities. The discovery of hand-labeled CD-R media containing MacOS 7.6 and 8.0 for CHRP (Common Hardware Reference Platform) offers intriguing opportunities for fans of pre-OS X MacOS releases on unsupported hardware.
CHRP, alongside PReP, is a term that might not ring a bell in 2025, but it was once significant. It refers to the Apple/IBM/Motorola collaboration, known as the AIM Alliance, which aimed to create lower-end workstations based on PowerPC processors with PC-style peripherals, targeting AIX, OS/2, Solaris, and even Windows NT and Novell Netware. The Register mentioned CHRP in 1999 and 2014, highlighting its potential.
The Windows NT on G3 iMac project brought CHRP back into the spotlight, and hacker 'Rairii' further expanded its reach by releasing Windows NT for GameCube/Wii. CHRP's goal was to unify PowerMac (designed for MacOS) and PowerPC Unix and NT workstations, but Apple's acquisition of NeXT and the return of Steve Jobs led to the cancellation of the Mac clone licensing program and the StarMax 6000, a unified workstation based on CHRP.
Apple also canceled its next-generation MacOS, 'Copland,' which was to become 'MacOS 8.' It was replaced with NeXTstep, leading to the creation of OS X. Some tech from the canceled project was released as MacOS 8 using the older, non-pre-emptively-multitasking MacOS kernel. Mac cloners were officially prohibited from running the new MacOS 8.
The recently rediscovered copies of MacOS 7.6 and 8 for CHRP hardware include two previously unseen components: a System Enabler for newer hardware and a NewWorld ROM containing the ROM part of Classic MacOS, called the Toolbox. As PowerMacs became faster, Apple removed the ability for later G4 and G5 PowerMacs to boot MacOS 8, limiting its use to the 'Classic' virtual machine on OS X.
The MacOS9Lives hackers have successfully run the last version of classic MacOS, 9.2.2, on the bare metal of some G4 models. They've been experimenting with the newly rediscovered older versions, their special Enabler, and soft-loadable ROM, as well as various older versions of MacOS. The result is remarkable: System 7 boots natively on the Mac mini G4! Members have tested multiple System versions, and several point-releases of 7.5 work, albeit with extensions disabled.
While the practical applications are limited, running MacOS 7.6 on a Mac mini G4 is a clever hack. It's a refreshing change from the recent surge in RAM prices, allowing for the use of new 1 GB hardware. The discovery offers a glimpse into the past and the potential for future exploration of classic MacOS on non-Apple PowerPC kits.
