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| PowerBook 540c - Did a thing (OS 8.6) |
Posted by: croissantking on 2026-02-07 17:57:06
Even more radical would be to get some sort of early Mac OS X running on it. One of the DPs, perhaps?
And 40 MB of RAM isn't necessarily a problem; Mac OS X 10.0 and 10.1 officially required 128 MB, but could install and run on 64. I once ran it on my Rev C Tray Loader iMac with 32 MB of RAM. Yes, thirty two megabytes. It was slow as h*** and thrashed the hard drive so hard I was worried it might die, but it actually worked!
Granted, this was on a Mac with a 266 MHz G3 running on a 66 MHz bus (compared to 100 MHz on a 16 MHz bus(!) ).
c
The RAM isn’t the main problem, it’s the architecture. Mac OS X needs Open Firmware, it’s fundamentally incompatible with anything Nubus/Slot Manager based. |
Posted by: CC_333 on 2026-02-07 19:20:33
The RAM isn’t the main problem, it’s the architecture. Mac OS X needs Open Firmware, it’s fundamentally incompatible with anything Nubus/Slot Manager based. Ah, I forgot about that.
Well, what other sort of exotic OS can a PPC-upgraded 540 run?
Does Rhapsody require OF?
c |
Posted by: croissantking on 2026-02-08 07:08:53
Ah, I forgot about that.
Well, what other sort of exotic OS can a PPC-upgraded 540 run? Maybe some form of era-appropriate PPC Linux? Tagging @demik.
Does Rhapsody require OF? Yeah definitely since it's essentially just an earlier version of Mac OS X, based on OpenStep. |
Posted by: joevt on 2026-02-08 16:40:26
The RAM isn’t the main problem, it’s the architecture. Mac OS X needs Open Firmware, it’s fundamentally incompatible with anything Nubus/Slot Manager based. The Mac OS X boot loader - BootX needs Open Firmware. So just create a new BootX that doesn't use Open Firmware.
Or, you can try creating a version of Apple's disk based Open Firmware that came with Copland D11E4 for the PDM Power Macs (6100, 7100, 8100). Maybe the boot loader that loads the disk base Open Firmware can be used as the basis for the new BootX?
In either case, you might need to make changes to the Mac OS X kernel (Open Firmware and BootX can apply kernel patches). And you'll need to create a platform expert kext and maybe some drivers, like XPostFacto has. You can use the disk to store NVRAM.
Anyway, anything is possible if you throw enough time and code at it. |
Posted by: croissantking on 2026-02-08 17:33:34
The Mac OS X boot loader - BootX needs Open Firmware. So just create a new BootX that doesn't use Open Firmware. Thanks for correcting me, that makes sense.
A monumental task, but not impossible - just improbable 😁 |
Posted by: adespoton on 2026-02-09 12:11:44
Maybe some form of era-appropriate PPC Linux? Tagging @demik.
Yeah definitely since it's essentially just an earlier version of Mac OS X, based on OpenStep. Not meaning to steal the thread... but I wanted to note this down somewhere. Since we've got G4 Minis running System 7.0 now, I wonder if we could modify the ROM or OF to allow "modern" PPC Macs to run NeXTStep and OpenStep as well....
For the 540c... it'd be really neat if we could force it to run System 6. But that would involve all sorts of hackery since it doesn't have OF available to provide hardware support outside the ROM and OS.
But a PPC upgraded 540c running System 6 would FLY! |
Posted by: demik on 2026-02-09 14:22:18
Maybe some form of era-appropriate PPC Linux? Tagging @demik.
Yeah definitely since it's essentially just an earlier version of Mac OS X, based on OpenStep. AFAIK there is no Linux for PPC upgraded blackbirds. Mainstream Linux PPC do expect some sort of OpenFirmware. They were patches to run on OF-less PowerMacs for Linux Kernel 2.4 back then, but it didn't include the PB540 |
Posted by: adespoton on 2026-02-09 15:39:45
AFAIK there is no Linux for PPC upgraded blackbirds. Mainstream Linux PPC do expect some sort of OpenFirmware. They were patches to run on OF-less PowerMacs for Linux Kernel 2.4 back then, but it didn't include the PB540 Ah that's right; it wasn't supported by m68kLinux. Maybe NetBSD PPC is a better target? |
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