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One of the most important features of modern CPUs is what's called the Protected Mode. And as luck would have it, the intersection of the Z80 features and the protected mode is exactly … nil. The thing doesn’t have it. 🤷‍♂️

So how does the title of this article make any sense? Let's see.

With great power comes great responsibility. Anyone who gets their own assembly code running on more or less popular 8-bit CPUs of the past, knows that in principle, they can do anything because they are allowed to. This includes especially access to the whole address space, and therefore comes with a whole set of very special problems, which some would call a security problem. (For others, it's more like the ONLY true way to push binary mnemonic representations through a CPU.)

The straitjacket called Protected Mode solves exactly this problem by enforcing very clear limits for all processes, which honestly makes perfect sense, as long as it is completely transparent to the programmer. Unfortunately, this is not possible with the Z80. Or is it?

Through Hackaday Author Jenny List we first became aware of Andy Hu's project. With the help of a few cheap ICs, the aged Z80 is actually taught a working protected mode, and the linked video of the actual author gives all the details.

Clever and interesting approach. Something to learn here.