Classic MacOS for non-Apple PowerPC kit rediscovered
(2025/12/08)
- Reference: 1765214269
- News link: https://www.theregister.co.uk/2025/12/08/classic_macos_for_nonapple_powerpc/
- Source link:
As well as the Mac clones, there were PC-style PowerPC machines – and a version of classic MacOS for them has just been rediscovered, enabling previously unimagined combinations.
The discovery of some hand-labelled CD-R media containing [1]MacOS 7.6 and 8.0 for CHRP opens up some intriguing possibilities for fans of the pre-OS X MacOS releases on hardware that doesn't officially support it… And the possibilities are not just limited to the now very rare machines it was intended for, way back in 1997.
You might be forgiven if you don't recognize the abbreviation CHRP in 2025. Along with its sibling PReP, these days it is one only a few old-time RISC workstation enthusiasts might instantly remember. The PowerPC chips on which Apple based its Mac computers from 1994 to 2006 were based on a design from IBM's high-end POWER machines, once RS/6000, later System p, and now sold as [2]IBM Power . The Apple/IBM/Motorola collaboration, [3]known as the AIM Alliance , was also planning on lower-end workstations based on PowerPC processors, but using PC-style peripherals and aimed at running AIX, OS/2, Solaris, and even Windows NT and Novell Netware.
[4]
The Register mentioned it [5]way back in 1999 and in slightly more detail [6]looking back from 2014 :
Working together, the AIM alliance developed a single-chip, POWER-based processor dubbed the PowerPC. In addition, they also developed two reference platforms for the new processor: the first was dubbed PReP (PowerPC reference platform), and its follow-on was CHRP (pronounced "chirp", common hardware reference platform), which incorporated Open Firmware.
The "common" in CHRP's name referred to the fact that the platform was intended to run a variety of operating systems on its PowerPC processor, including the Mac operating system, Microsoft Windows NT, IBM OS/2, Sun Solaris, and IBM AIX. Unfortunately for the alliance, however, CHRP never caught on – although IBM used it for some of its RS/6000 boxes.
In recent years CHRP has returned blinking into the daylight, in part due to the remarkable [7]Windows NT on G3 iMac project we covered 18 months ago. Earlier this year, the inspired hacker "Rairii" that got NT working on the G3 went even further and released [8]Windows NT for GameCube/Wii .
CHRP was meant to bring together the two worlds of PowerMac (intended for MacOS) and PowerPC Unix and NT workstations together. Motorola's [9]Information Systems Group had a unified workstation, the [10]StarMax 6000 , ready to launch… Then Apple acquired NeXT, bringing Steve Jobs back – and he immediately cancelled the Mac clone licensing program. Although MacWorld [11]put it on the cover [PDF – the article is on page 87], the CHRP-based StarMax 6000 never shipped.
[12]
[13]
Apple cancelled its [14]next-generation MacOS "Copland." Copland, which was to have been "MacOS 8," was replaced with NeXTstep, to create what became OS X. Some tech salvaged from the cancelled project was released as MacOS 8 using the older, non-pre-emptively-multitasking MacOS kernel. Officially, Mac cloners were [15]not allowed to run the new MacOS 8.
[16]Rebuilding VisiCorp's Visi On UI reveals how Apple defined the GUI era
[17]LisaGUI recreates Apple's innovative computer OS, without emulating it
[18]Bring back your old Mac: 5 ways to refresh the OS on elderly Apples
[19]AmiBrowser brings 21st century web to 20th century Amigas
What's just been rediscovered are copies of a special versions of MacOS 7.6 (the last iteration of System 7, the OS that Mac-compatibles were allowed to run), and its successor MacOS 8, for CHRP hardware. These contain two previously unseen components: a [20]System Enabler for newer hardware, and a [21]NewWorld ROM containing the ROM part of Classic MacOS, called the Toolbox, for that hardware.
As PowerMacs got faster, to encourage Mac owners to adopt the new OS X, Apple removed the ability for later G4 and G5 PowerMacs to boot MacOS 8. You could only run it in the "Classic" virtual machine on OS X. As we [22]mentioned back in September , the hackers of [23]MacOS9Lives have managed to get the last version of the classic MacOS, 9.2.2, running on the bare metal of some models of G4. Now some of the members have been experimenting with these newly rediscovered older versions and their special Enabler and soft-loadable ROM and various older versions of MacOS.
The result is that " [24]System 7 natively boots on the Mac mini G4! " Member "Jubadub" reports that they tested System version 7, 7.0, 7.1, 7.5, 7.6, 8.0, 8.1, 8.5, 8.6, 9.0, 9.1, and 9.2. They've been busy. Several point-releases of 7.5 work, but only with extensions off, which renders them a bit useless, but 7.6 and 8.1 work well. MacOS 8.1 is notable for being the last version of MacOS for 680x0-based Macs, and the first version to support HFS+, as used in modern macOS until version 10.12 "Sierra" in 2016.
[25]
What are the practical applications of this? Not many. MacOS 7.6 only got two releases, 7.6.0 and 7.6.1, which The Reg FOSS desk used to run on a Mac Classic II with a vast 10 MB of RAM. This is a tiny, relatively fast OS, and now you can use it on a [26]Mac mini G4 , a gigahertz-class machine that can take a whole gigabyte of RAM, although MacOS 7.6 can't display a number that big in its "About this Mac" dialog box. But it's a clever and fun bit of hackery.
MacOS 7.6.1 officially wanted 12 MB to run, but a [27]Classic II can't take that much. So we used [28]Connectix RAMdoubler and it worked fine. With RAM prices going crazy recently resulting in [29]new 1 GB hardware appearing in 2025, only wanting 1 percent that much is a refreshing change. ®
Get our [30]Tech Resources
[1] https://macintoshgarden.org/apps/mac-os-chrp-releases-powerpc-common-hardware-reference-platform
[2] https://www.ibm.com/products/power
[3] https://www.theregister.com/1999/04/13/apple_to_move_on_merced_3/
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[5] https://www.theregister.com/1999/05/14/developer_community_to_standardise_powerpc/
[6] https://www.theregister.com/Print/2014/01/24/thirty_years_of_the_apple_macintosh_p1
[7] https://www.theregister.com/2024/07/17/windows_nt_on_powermac_g3/
[8] https://github.com/Wack0/entii-for-workcubes
[9] https://web.archive.org/web/19961222141436/http://www.mot.com/
[10] https://lowendmac.com/1997/motorola-starmax-6000/
[11] https://vintageapple.org/macworld/pdf/MacWorld_9710_October_1997.pdf
[12] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[13] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[14] https://www.theregister.com/2014/02/12/ten_apple_greatest_device_fails/
[15] https://www.sfgate.com/business/article/Apple-Won-t-OK-Newest-Computers-From-Clone-Makers-2812072.php
[16] https://www.theregister.com/2025/12/08/visi_on_deep_dive/
[17] https://www.theregister.com/2025/11/24/lisagui_lisaos_apple/
[18] https://www.theregister.com/2025/09/13/refresh_an_old_mac/
[19] https://www.theregister.com/2025/08/28/amiga_web_browser_amibrowser/
[20] https://apple.fandom.com/wiki/System_Enabler
[21] https://apple.fandom.com/wiki/New_World_ROM
[22] https://www.theregister.com/2025/09/13/refresh_an_old_mac/
[23] https://macos9lives.com/
[24] https://macos9lives.com/smforum/index.php?topic=7711.0
[25] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[26] https://lowendmac.com/2014/g4-mac-mini-a-second-class-mac/
[27] https://lowendmac.com/1991/mac-classic-ii/
[28] https://www.theregister.com/2021/11/15/softram95/
[29] https://www.theregister.com/2025/12/01/raspberry_pi_5_1gb/
[30] https://whitepapers.theregister.com/
The discovery of some hand-labelled CD-R media containing [1]MacOS 7.6 and 8.0 for CHRP opens up some intriguing possibilities for fans of the pre-OS X MacOS releases on hardware that doesn't officially support it… And the possibilities are not just limited to the now very rare machines it was intended for, way back in 1997.
You might be forgiven if you don't recognize the abbreviation CHRP in 2025. Along with its sibling PReP, these days it is one only a few old-time RISC workstation enthusiasts might instantly remember. The PowerPC chips on which Apple based its Mac computers from 1994 to 2006 were based on a design from IBM's high-end POWER machines, once RS/6000, later System p, and now sold as [2]IBM Power . The Apple/IBM/Motorola collaboration, [3]known as the AIM Alliance , was also planning on lower-end workstations based on PowerPC processors, but using PC-style peripherals and aimed at running AIX, OS/2, Solaris, and even Windows NT and Novell Netware.
[4]
The Register mentioned it [5]way back in 1999 and in slightly more detail [6]looking back from 2014 :
Working together, the AIM alliance developed a single-chip, POWER-based processor dubbed the PowerPC. In addition, they also developed two reference platforms for the new processor: the first was dubbed PReP (PowerPC reference platform), and its follow-on was CHRP (pronounced "chirp", common hardware reference platform), which incorporated Open Firmware.
The "common" in CHRP's name referred to the fact that the platform was intended to run a variety of operating systems on its PowerPC processor, including the Mac operating system, Microsoft Windows NT, IBM OS/2, Sun Solaris, and IBM AIX. Unfortunately for the alliance, however, CHRP never caught on – although IBM used it for some of its RS/6000 boxes.
In recent years CHRP has returned blinking into the daylight, in part due to the remarkable [7]Windows NT on G3 iMac project we covered 18 months ago. Earlier this year, the inspired hacker "Rairii" that got NT working on the G3 went even further and released [8]Windows NT for GameCube/Wii .
CHRP was meant to bring together the two worlds of PowerMac (intended for MacOS) and PowerPC Unix and NT workstations together. Motorola's [9]Information Systems Group had a unified workstation, the [10]StarMax 6000 , ready to launch… Then Apple acquired NeXT, bringing Steve Jobs back – and he immediately cancelled the Mac clone licensing program. Although MacWorld [11]put it on the cover [PDF – the article is on page 87], the CHRP-based StarMax 6000 never shipped.
[12]
[13]
Apple cancelled its [14]next-generation MacOS "Copland." Copland, which was to have been "MacOS 8," was replaced with NeXTstep, to create what became OS X. Some tech salvaged from the cancelled project was released as MacOS 8 using the older, non-pre-emptively-multitasking MacOS kernel. Officially, Mac cloners were [15]not allowed to run the new MacOS 8.
[16]Rebuilding VisiCorp's Visi On UI reveals how Apple defined the GUI era
[17]LisaGUI recreates Apple's innovative computer OS, without emulating it
[18]Bring back your old Mac: 5 ways to refresh the OS on elderly Apples
[19]AmiBrowser brings 21st century web to 20th century Amigas
What's just been rediscovered are copies of a special versions of MacOS 7.6 (the last iteration of System 7, the OS that Mac-compatibles were allowed to run), and its successor MacOS 8, for CHRP hardware. These contain two previously unseen components: a [20]System Enabler for newer hardware, and a [21]NewWorld ROM containing the ROM part of Classic MacOS, called the Toolbox, for that hardware.
As PowerMacs got faster, to encourage Mac owners to adopt the new OS X, Apple removed the ability for later G4 and G5 PowerMacs to boot MacOS 8. You could only run it in the "Classic" virtual machine on OS X. As we [22]mentioned back in September , the hackers of [23]MacOS9Lives have managed to get the last version of the classic MacOS, 9.2.2, running on the bare metal of some models of G4. Now some of the members have been experimenting with these newly rediscovered older versions and their special Enabler and soft-loadable ROM and various older versions of MacOS.
The result is that " [24]System 7 natively boots on the Mac mini G4! " Member "Jubadub" reports that they tested System version 7, 7.0, 7.1, 7.5, 7.6, 8.0, 8.1, 8.5, 8.6, 9.0, 9.1, and 9.2. They've been busy. Several point-releases of 7.5 work, but only with extensions off, which renders them a bit useless, but 7.6 and 8.1 work well. MacOS 8.1 is notable for being the last version of MacOS for 680x0-based Macs, and the first version to support HFS+, as used in modern macOS until version 10.12 "Sierra" in 2016.
[25]
What are the practical applications of this? Not many. MacOS 7.6 only got two releases, 7.6.0 and 7.6.1, which The Reg FOSS desk used to run on a Mac Classic II with a vast 10 MB of RAM. This is a tiny, relatively fast OS, and now you can use it on a [26]Mac mini G4 , a gigahertz-class machine that can take a whole gigabyte of RAM, although MacOS 7.6 can't display a number that big in its "About this Mac" dialog box. But it's a clever and fun bit of hackery.
MacOS 7.6.1 officially wanted 12 MB to run, but a [27]Classic II can't take that much. So we used [28]Connectix RAMdoubler and it worked fine. With RAM prices going crazy recently resulting in [29]new 1 GB hardware appearing in 2025, only wanting 1 percent that much is a refreshing change. ®
Get our [30]Tech Resources
[1] https://macintoshgarden.org/apps/mac-os-chrp-releases-powerpc-common-hardware-reference-platform
[2] https://www.ibm.com/products/power
[3] https://www.theregister.com/1999/04/13/apple_to_move_on_merced_3/
[4] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=2&c=2aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D2%26raptor%3Dcondor%26pos%3Dtop%26test%3D0
[5] https://www.theregister.com/1999/05/14/developer_community_to_standardise_powerpc/
[6] https://www.theregister.com/Print/2014/01/24/thirty_years_of_the_apple_macintosh_p1
[7] https://www.theregister.com/2024/07/17/windows_nt_on_powermac_g3/
[8] https://github.com/Wack0/entii-for-workcubes
[9] https://web.archive.org/web/19961222141436/http://www.mot.com/
[10] https://lowendmac.com/1997/motorola-starmax-6000/
[11] https://vintageapple.org/macworld/pdf/MacWorld_9710_October_1997.pdf
[12] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[13] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=3&c=33aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D3%26raptor%3Deagle%26pos%3Dmid%26test%3D0
[14] https://www.theregister.com/2014/02/12/ten_apple_greatest_device_fails/
[15] https://www.sfgate.com/business/article/Apple-Won-t-OK-Newest-Computers-From-Clone-Makers-2812072.php
[16] https://www.theregister.com/2025/12/08/visi_on_deep_dive/
[17] https://www.theregister.com/2025/11/24/lisagui_lisaos_apple/
[18] https://www.theregister.com/2025/09/13/refresh_an_old_mac/
[19] https://www.theregister.com/2025/08/28/amiga_web_browser_amibrowser/
[20] https://apple.fandom.com/wiki/System_Enabler
[21] https://apple.fandom.com/wiki/New_World_ROM
[22] https://www.theregister.com/2025/09/13/refresh_an_old_mac/
[23] https://macos9lives.com/
[24] https://macos9lives.com/smforum/index.php?topic=7711.0
[25] https://pubads.g.doubleclick.net/gampad/jump?co=1&iu=/6978/reg_software/oses&sz=300x50%7C300x100%7C300x250%7C300x251%7C300x252%7C300x600%7C300x601&tile=4&c=44aTdYhk7lnxrSRDd2pRkgwAAAABg&t=ct%3Dns%26unitnum%3D4%26raptor%3Dfalcon%26pos%3Dmid%26test%3D0
[26] https://lowendmac.com/2014/g4-mac-mini-a-second-class-mac/
[27] https://lowendmac.com/1991/mac-classic-ii/
[28] https://www.theregister.com/2021/11/15/softram95/
[29] https://www.theregister.com/2025/12/01/raspberry_pi_5_1gb/
[30] https://whitepapers.theregister.com/
Re: CHRP is....
Fruit and Nutcase
Going back a few more years, parallel ports on PCs were handy whenever there was a need to transfer a few tens of megabytes between PCs/faster than the serial interfaces on the PCs of the era.
Then along came Microsoft and bundled Interlnk with MS-DOS...
[1]https://en.wikipedia.org/wiki/Laplink
I still have a LapLink cable...
[1] https://en.wikipedia.org/wiki/Laplink
"vast 10 MB of RAM"
897241021271418289475167044396734464892349863592355648549963125148587659264921474689457046465304467
Paid 90 squid 64GB of DDR4 but two months ago, went to buy more yesterday and it's almost £400! Lean is the future - AI gobbling all planetary resources to enslave us all.
Re: "vast 10 MB of RAM"
Dan 55
Perhaps we'll be forced to finally drop Electron/WebView2/XAML/JavaScript framework bloat with libraries for left padding and ten levels of abstraction and go back to what we should be doing which is compiled software with a handful of libraries.
obligatory "of course it runs..." comment
coredump
Best wishes from this find for the vintage computing and MacOS enthusiasts, no doubt some basement gear will be enjoyed again as a result.
It's also worth a mention that some of this PPC kit could have an alternative OS for support, as NetBSD may run some of it:
https://wiki.netbsd.org/ports/ofppc/
"NetBSD/ofppc is the port of NetBSD to the OpenFirmware, and CHRP (Common Hardware Reference Platform) PowerPC machines, and original implementation of NetBSD for the PowerPC processor."
https://wiki.netbsd.org/ports/prep/
"NetBSD/prep is the port of NetBSD to early PReP (PowerPC Reference Platform) machines."
There are a few other PowerPC-based NetBSD ports as well, so if your gear doesn't fit the above it might be worth a look at the rest of the list: https://wiki.netbsd.org/ports/
Motorla 603e and Apple MacPro G4
Zolko
I had those. With System 7. Funnily, I put BeOS on them, and also Linux. PPC Linux 1997, based on RedHat with kernel 2.1.125 .... those were the times ... sweet memories ... kids were cute, sun was shining, future was ahead
Last month's news
Chris Warrick
> What's just been rediscovered are [...]
That’s a funny way to spell a month ago .
CHRP is....
Common Hardware Reference Platform.
The intention was to allow third party manufacturers to create alternative 'blessed' Macs and compete with the proliferation of Windows PCs. I believe SJ ended the program when he realized it would cut deeply into Apple's hardware revenue.
I did some work on the CHRP in the 1990s as it included a parallel port, which would have been very useful for driving the plethora of PC compatible printers.