[Symmetry]

Last I heard they're still limited to sims and are concentrating on patent filings. The bootstrap strategy is LLVM (once they get around LLVM assuming addresses are integers as opposed to the Mill's compound things) and to get Linux running on top of L4 which seems doable[1]. They say they're looking for a niche to start in before going after PCs.

[1]http://l4linux.org/

[xorcist]

Why on L4? Is Mill somehow tied to it, architecture-wise? Or is it just that L4 has a smaller footprint and is easier to port?

[willvarfar]

Its about footprint. We certainly will run Linux on the Mill, but its work we don't have to put on the critical path. L4 is just a familiar lightweight OS, and we're keen to play with Mill-specific security features which are particularly applicable to microkernels too.

When we do port Linux, I expect it to become much more microkernel like, as in why would you want your disk drivers to be able to read write video memory etc?

[xorcist]

> why would you want your disk drivers to be able to read write video memory etc?

That is a much bigger issue than the CPU architecture, as it has more to do with how the peripheral hardware works (firmware, DMA, etc.), but I appreciate the effort.

[willvarfar]

Well its how the CPU architecture exposes the hardware to software i.e. drivers. The Mill does MMIO but doesn't have rings.

[Symmetry]

Because the Mill has a single address space with memory protection, which works a lot better with L4 than it does with Linux. Porting Linux directly would probably be possible, but a huge effort the team wouldn't be able to pull off without a lot of extra resources.