I'm not convinced that it's really cheaper to hire (good) Linux devs for this kind of work, and even if it were I doubt that's their biggest concern. A bunch of

I'm not convinced that it's really cheaper to hire (good) Linux devs for this kind of work, and even if it were I doubt that's their biggest concern. A bunch of "commodity" developers wouldn't be able to build a complex real-time system like that and meet those targets - look what happened to the London Stock Exchange a couple of years back when they tried that. It seems much more likely to me that the real underlying driver is the level of customisability they need. They're talking about making scheduler changes to the kernel and building the whole OS themselves - that's a level of control Windows (or any other closed-source option) doesn't offer.