RVP wrote: > On Wed, 11 Oct 2023, Simon Burge wrote: > > > RVP wrote: > > > >> I think what David's looking for is something akin to Linux's > >> > >> /proc/sys/kernel/random/boot_id > >> > >> something which only changes on every boot but is otherwise stable. > > > > I'm curious how well this boot_id works on Linux for things like a > > embedded system (eg router) that boots from a ram disk and doesn't have > > an RTC. Essentially a similar problem to our long-running entropy > > discussion. > > On embedded systems without an RTC, you _could_ get the same UUID in rare > cases. But I think this would be a bug, because on Linux, any kind of jitter- > source (interrupt timing, for instance) would perturb the generated UUID.
Hopefully! Even though this jitter might not be high entropy, it should (in theory) be enough to give a differnet UUID each boot. Assuming of course that the boot_id is generated after interrupts are enabled and some jitter has been processed :). Cheers, Simon.