Well in my cases, the user-land programs do not require any RT awareness other than being able to periodically empty a FIFO or somesuch. As long as the client can check the FIFO every second or so all should be well. We would implement the RT hardware monitoring code as a hack directly to the microkernel, inserting our code into the timer chain. That's the plan anyways. We are currently tinkering with versions of RT Linux, but I liketo keep considering Hurd for this too just because of its experimental nature.
Thomas Bushnell, BSG wrote:
No particular effort has gone into making the Hurd RH aware, and RT Mach is nearly a dead-end, in that nobody is particularly working on it any more. It is free software (it's just a set of mods to standard Mach), and you could find it somewhere on the net, though I'm not sure where. However, none of the Hurd servers make any kind of RT guarantees, so a RT program would not be able to use them in any critical sections.