As someone who runs many architectures, I do know what it means. I wasn't aware of the author's experience because Chris didn't offer any details, but that link

As someone who runs many architectures, I do know what it means. I wasn't aware of the author's experience because Chris didn't offer any details, but that link does offer some clues. The reality is that there have always been ways to have multiple architectures supported simultaneously, and they're neither all that complicated nor kludgy, unless one has to support poorly written software. Even back in the m68k -> SPARC transition, people had clean ways to keep things separate and clean, and to support the same homes and binaries across both architectures simultaneously. We had the PowerPC to x86 transition show us how it can be done so cleanly that many people had no idea what architecture they were running. The same can be said about the x86 to ARM transition with Apple now. (Open)VMS explicitly supports multiple simultaneous architectures. We have ways of making fat binaries for other OSes, too - we had them back then, and we have them right now. We also have examples of doing it wrong: Microsoft Windows. The idea that people had to know and choose whether they want a 32 bit or 64 bit OS is still incredibly stupid, as is needing to choose 32 bit or 64 bit software. If people are writing binary files in endian specific ways, or with data sizes that depend on the specific processor, that's shitty programming. Any software doing that never had any sort of portability in mind, so that's not a good example at all. That kind of software is chided in public in the open source world, or at very least people know to isolate it and run it where it's safe. Sharing a user's home across multiple systems, perhaps with different architectures, isn't to save disk space, by the way. Expecting users to manage data and configurations across multiple machines isn't reasonable. Shared homes is still both normal and common in larger environments. If the author disagrees, it'd be nice to hear some actual examples of why it's a problem. After all, ARM isn't going away and RISC-V is only going to become more common.