[orev]

To me, bare metal has meant running on an OS that’s directly on the hardware, instead of a virtual machine. However, I can see your point about what it could mean (i.e. the software itself is compiled to directly run on the hardware with no OS), but I’m struggling to think of a time when anything worked like that. You have to go really, really far back in history to apply that definition to general purpose computing systems. I’m left thinking that it would only really apply to embedded systems and hardware controllers, and many of those now even have some kind of micro-os that runs on them.

[anothergoogler]

Not virtualized doesn't mean bare metal. I think the term would make more sense to you if you worked through "Linux from Scratch." There are things between embedded and running a full Linux OS.

[ofrzeta]

What would those things be? Maybe it's a continuum but concepts are not continuous. Surely there are various degrees of OS but if it's anything that manages the "bare" hardware it's something like an OS. Arguably you could also call Xen Dom0 an operating system.