Over the many years Apple Computer have been in operation, they have made a success of nearly-seamlessly transitioning multiple times between both operating systems and their underlying architecture. There have been many overlapping versions, but there’s always a point at which a certain OS won’t run on newer hardware. Now [Jubadub] has pushed one of those a little further than Apple intended, by persuading classic Mac System 7 to run on a G4.
System 7 was the OS your Mac would have run some time in the mid ’90s, whether it was a later 68000 machine or a first-gen PowerMac. In its day it gave Windows 3.x and even 95 a run for their money, but it relied on an older Mac ROM architecture than the one found on a G4. The hack here lies in leaked ROMS, hidden backwards compatibility, and an unreleased but preserved System 7 version originally designed for the ’90s Mac clone programme axed by Steve Jobs. It’s not perfect, but they achieved the impossible.
As to why, it seems there’s a significant amount of software that needs 7 to run, something mirrored in the non-Mac retrocomputing world. Even this hack isn’t the most surprising System 7 one we’ve seen recently, as an example someone even made a version for x86 machines.
Thumbnail Image Art: Apple PowerMac G4 by baku13, CC BY-SA 3.0
i have a huge amount of classic mac applications i obtained from workstations in computer labs able to reach across university campases via appletalk networks. i would drive to some random college town, find the computer lab, break out my portable scsi drive, and download anything i could. then i would spend the next week cracking the programs i got to eliminate copy protection (the ones involving dongles were particularly easy to bypass — the jmp instructions were always so obvious). i haven’t yet found a suitable showcase for this software but a g4 running system 7 seems perfect.