hi again,
[OT: First of all a great thanks to everyone at TU Dresden for the interesting discussions and pleasant company during our visit last week.]
Following a discussion with Jan Glauber Friday evening on the HP Somersault API, which does failover by making sure processes on a standby machine receive the exact same inputs as those on the master machine, I wondered if anyone knows if the PentiumII local APIC is precise enough that you can do completely deterministic scheduling, say, in Fiasco?
It seems to me that one could implement an OS-level failover system by wrapping the OS in an I/O environment (like NomadBIOS ;-)) which would somehow ensure that the exact same input was received at both the master and the slave hosts, provided that the scheduling performed by the kernel scheduler could be performed with clockcycle precision (otherwise race conditions would allow things to get out of sync).
Does anyone have an opinion as to whether or not this might be possible using current Intel hardware?
best,
Jacob
l4-hackers@os.inf.tu-dresden.de