sr (nobody.delete@this.nowhere.com) on September 25, 2021 11:52 am wrote:
>
> But isn't that just what you need for limited-access function?
>
> Or how is it done in software?

It sounds like you never had to use segments.

You sweet summer child.

There's a reason people hated them. Different pointers for "far" accesses, and having to annotate and carry this all around. It wasn't just a portability nightmare (it's not like most PC programmers cared about portability anyway), it was just really inconvenient and bad in general.

And it pollutes everything. Even if you write code that only ran on a 32-bit CPU, and you never needed to use segments just to escape the 64kB limits, the fact that you then had some code that wanted to interact across segments means that you have to have all kinds of wrapper functions.

You can hide it from a lot of applications - and people did (only by having the applications not use segments!), but you ended up having it show up in system interfaces that had to deal with legacy cases or with the crazy apps that wanted to use segments after all.

Trust me. You don't want segments. It really sounds like you've read the technical descriptions, not had to deal with the reality. It's just no fun dealing with multiple different pointer formats, and avoiding it entirely by dealing in all "fat pointers" is horrendously bad for your sanity and for performance.

Linus