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.
“Nearly-seamlessly”?!?!?!? As someone who worked on a 68k Quadra until iBook came out at the turn of the century, I know that, only as long as you upgraded to the latest hardware, was the transition was smooth. Apple suddenly cut off support and abandoned those with older Macs, just like they did with the excellent Cyberdog, Hypercard, and come to think of it, the entire Apple II lineup! And behind the scenes, projects like the infamous “Star Trek” failed big. Sure, they have transitioned multiple times(personally, I haven’t touched any Apple Silicon hardware), but “nearly seemlessly,” -NOT. Please, let’s not invite “Apple Fangirl” accusations, shall we?
Cyberdog (and OpenDoc in general) was an absolute mess.
Um, I think that was about the use of Fat Binaries (later: Universal Binaries) and inclusion of emulation on the OS level.
When the transition between Mac OS 8/9 to X took place, the Carbon API provided a bridge between both worlds, too.
Or let’s take Classic Environment that virtualized a copy of MacOS 9 on Mac OS X 10.0 to 10.4 (PPC). Or Blue Box (with MacOS 8.6) on Rhapsody.
Or the Rosetta emulation in Intel versions of 10.4/10.5/10.6..
Traditionally, in short, the next generation MacOS often contains a compatibility layer of some sort.
It won’t last long, but it’s there for a while.
Way back in the mid-90s, it was the 680EC40 CPU emulator baked into the PowerPC versions of System 7 and MacOS 8/9.
There even were third-party FPU emulators such as Power FPU that would provide Motorola FPU emulation by using the PowerPC FPU.
In general, from an user point of view, the upgrade path was mostly smooth, thus.
Unless you were stuck with an 1994 era 68k Macintosh in 2004, of course.
But on PC side that’s like using an 1992 era 286 PC running Windows 3.1 in 2002 and wondering about lack of support.
No offense, I think these points of you are valid.
Personally, I think there was no need to drop Carbon support or removal of Classic Environment or Rosetta 1, for example.
That was more of a political reason than a technical one.
PS: I think that in the mid-90s it was clear that 68040 had no future (the 68060 would have bought some time, though).
The multimedia hype and the early web made it clear that the PowerPC’s power was being wanted.
Also many then-modern games, such as Sam&Max Hit The Road etc. wanted so see a PowerPC, if possible.
https://www.mobygames.com/game/745/sam-max-hit-the-road/cover/group-80306/cover-910792/
Especially on a defacto single-tasking OS such as System 7, the PowerPC was a win.
While System was very easy to use and quick/snappy on low load,
once you ran monstrosities such as Netscape 2 or 3 the raw power of a PowerPC was needed desperately.
Just like a Pentium helped old, lightweight Windows 3.1 appear to be running Netscape or multimedia programs far less painfully.
I’m not saying that the Motorola 68k was poor or something.
It shined on an 68040 Macintosh running A/UX, for example.
Here, real multitasking was available – and limited System 7 application compatibility, as well. Great for power users, in short.
Such a system was great as an AppleTalk server, for example,
because multiple files by multiple Macs on the network could be handled simultanously.
Also, some 68040 Mac could be “upgraded” with a PowerPC CPU card.
They were capable of running both 68k and PPC versions of System 7.
https://en.wikipedia.org/wiki/Macintosh_Processor_Upgrade_Card
Speaking under correction, I was more of a DOS user in the early-mid 90s. ;)
Apple’s multiple transitions to different architectures has been one of the most impressive technical feats in the industry. Workstation manufacturers switched from 68K to RISC in the 1980s, because they only cared about source code portability (which was really important, obviously). But they never had to manager binary compatibility. PCs simply kept upward binary compatibility in hardware – with the upshot that modern x86 / x64 CPUs can still run real-mode 8086 applications (though 16-bit apps are no longer allowed AFAIK).
But developing emulators that can run binaries from the previous architecture at usable speeds is truly astounding. The Gary Davidian 68LC040 interpretative emulator was a ground-breaking piece of software, amazingly efficient at about 1/3 to 1/12 of the speed of original instructions (compared to 1/54 in emulators such as QEMU and MAME). I remember using a Performa 5200/75 in early 1996 and being genuinely impressed by the compatibility of legacy software and the performance of new software, it was good.
Transitive Technology’s Rosetta used to emulate PowerPC on Intel, again, was a game-changer. My use of early Intel Macs in 2010 (I was a late adopted) did appear seamless
For a software ecosystem that didn’t have the girth that x86 did, it pays to leave as few behind.