[TeMPOraL]

But they didn't have technology yet to do it properly, so it was trivial for people to sever the tie and install alternative OSes - trivial enough that it was also easy to teach others how to do it.

Now, the tech to make that tie near-unbreakable exists.

[dghlsakjg]

Can you install an alternate os on the original Mac or a C64?

I was only aware of that possibility for pc clones

[TeMPOraL]

You could if someone made one, presumably. OS is just a program, after all - and 20th century hardware couldn't stop you from completely rewriting the software on it.

The problem today is that modern computers are designed to prevent this, by means that can provide mathematical proofs you won't be able to defeat the protection in any useful sense before the Sun burns out. You have tamper-proof fuses embedded in microchips, and some systems have cryptographic hashes in every major component to prevent you from replacing something too hard to reprogram, etc.

We're yet to see a fully locked down computer (smartphones are close), but the tech for it is there.

[ben_w]

I briefly tried some flavour of linux on a Performa 5200, PPC chip.

Here's an alternative OS for the C64, though I no longer have such a machine to try it on: https://www.c64-wiki.com/wiki/Contiki