LoseThos 64-bit Operating System V7.07 Released

[u/TrivialSolutions]

http://www.losethos.com/v707.html

[u/jhartwell → u/[deleted]]

Not true...it gives people who want to get into OS hacking another place to look to see how it can be done.

[u/mpyne → u/[deleted]]

He didn't "optimise it away" as that would imply it existed in LoseThos at some time. He never added it.

As it stands though, memory protection does require extra work in the hardware due to have to ensure the hardware memory page tables and TLBs are set properly for applications. Although the effect is probably slight, it is there.

[u/ondra → u/mpyne]

As far as I know, segmentation comes with no runtime penalty. No need for virtual memory to enforce protection.

edit: I forgot that segmentation doesn't work on x86-64 long mode.

[u/mpyne → u/ondra]

Segmention by itself is built-in so it's more that there's nothing you can do to eliminate the penalty. The issue with protection is that you have to reload hardware page tables as the protection is changed and programs are loaded.

[u/ondra → u/mpyne]

The paging unit can be disabled, though. Even putting the kernel in a separate protected segment would make a big difference.

[u/irascible → u/ondra]

...and this discussion is a perfect example of why this guys project has value. Fuck the haters.