Somebody with more info is welcome to chime in, but this is what I've gathered from reading Apple Dev Notes and User Guides for Motorola chips:
Multiprocessor was weird in early Macs. The first Mac with an MP setup was the 9500/180MP. It's a cooperative multitasking arrangement and requires programs to be specifically multiprocessor aware to take advantage of that second processor, which otherwise sits idle without the first processor explicitly feeding it instructions from those MP-aware programs. Because of the weird hardware arrangement, OS X and Linux have no support for the second processor. The same is true for their followup machine, the 9600/200MP.
Yes. We had almost this exact thread a few months ago and the same claim about the multi-CPU 604s being incapable of SMP was thrown out, but Linux can indeed use them.OS X may not, but Linux on my 9500/180MP is perfectly happy to detect and use both CPUs.
BeOS will use all four in a Daystar Genesis MP. Haven't tried any flavor of Linux on it.OS X may not, but Linux on my 9500/180MP is perfectly happy to detect and use both CPUs.
The primary limitation of these machines with their use of CMP instead of SMP is that the memory controller/PCI bridges Apple used were unable to directly interface with more than one processor.
Yeah, that's why I put the question mark in my reply. There's some really old traffic on the kernel mailing lists and comments in the kernel code that suggest that either it doesn't do interrupt steering in quite the same way as, for instance, Intel's APIC does, or if it does the kernel developers were having trouble making it work. The word on the street seems to be that the SMP code for the Beige PowerMacs was never particularly reliable, and that problem got worse/was never really solved when the SMP infrastructure in Linux was drastically improved post-2.4, which eliminated most of the "Big Lock", but since I have zero experience with Linux on these machines I don't know how accurate a summation that is.I'm not certain how interrupt handling happens under that scheme. I know Grand Central collects interrupts but I'm not sure how they get processed and sent back to the CPUs. But all the hardware should look identical to the two possible CPUs once one has requested and been granted control of the bus.
I can't find photo examples, but I believe they compiled special versions of Photoshop to take advantage of the MP capabilities around this time (97-98), which would've made it maybe 4.0 but more like 5.0… not sure 100%. I do know the dual G5 had a special version of Photoshop: I remember setting up the MP G5 tower at the broadcast group I worked for and the Photoshop box had a decal on it indicating it was for MP systems. Unless it was all some hallucination…Yep they did.. yep it was 9600/200MP. It was pretty much useless as the programs wasn't really supported (I think Adobe was the only one that was supported). I have one of those CPU cards somewhere, I've only seen 200mhz dual.
I am curious what kind of software it was?
Cheers
AP
Ah, Copland. It's too bad it was so mismanaged, as it was actually a rather promising concept, and had it not been cancelled, what we now know as Mac OS X would probably be based on it instead of NeXTSTEP.Sure did. The System just never made it to market: see Chapter 4 of https://www.pagetable.com/docs/copland_docs/book/Mac OS 8 Revealed.pdf#page1 .