Alan Altmark wrote:
On Monday, 11/13/2006 at 08:02 CST, "McKown, John"
<[EMAIL PROTECTED]> wrote:
The zSeries TOD clock is only sync'ed to the HMC (or SE) clock with a
Power On Restart (or is it RESET?), not at IPL time or LPAR activation
time. A POR affects all LPARs, obviously.
My informant says otherwise: When you activate an LPAR it will resync its
TOD to the CEC TOD. After that, any STP/ETR-induced changes to the CEC
TOD are invisible to the partition unless it explicitly enables to be
notified of TOD changes. z/OS will do that. z/VM won't. (And, right,
IPL does not resync the TOD.)
Alan Altmark
z/VM Development
IBM Endicott
Are you sure this is accurate (or not misleading)? My impressions from
empirical evidence on a z900 is that the CEC TOD is not the same as the
HMC (or SE) clock; that it takes a POR to set the CEC TOD clock from the
HMC or SE clock, while an activate sets the LPAR TOD based on the CEC
TOD clock and both increment in sync. In other words, if you change the
SE clock and want it to propagate, a POR was necessary to start the
process. Can't speak for interactions with ETR as we have never had one.
We are now on a z9, but have only been there for four months. The CEC
TOD increment finally seems to have accuracy comparable to a $30 watch,
and we haven't had to correct its TOD clock yet.
--
Joel C. Ewing, Fort Smith, AR [EMAIL PROTECTED]
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