>>> On 3/3/2012 at 01:12 PM, Paul Gilmartin <[email protected]> wrote: > What does Linux for z use for clock steering? I understand it > was never ETR-savvy (nor was z/VM?) I imagine it might be > done by letting the ETOD clock run free and allowing NTP to > update parameters of a software offset used by all system time > services (kinda like CVTLSO).
Most Linux operating systems read the hardware clock during the startup process, and use that to set the system clock. NTP takes over from there, but only affects the system clock, not the hardware clock. The system only tries to set the hardware clock when shutting down. There is only one source of time on Linux, and that's from the kernel via the gettimeofday syscall. So, all processes go to the same place to get their time information. There were some changes to the kernel a while ago that made it aware of ETR/STP. I never looked at the code to see if it involved any attempts at modifying the hardware clock. Mark Post ---------------------------------------------------------------------- For IBM-MAIN subscribe / signoff / archive access instructions, send email to [email protected] with the message: INFO IBM-MAIN
