On Friday, 10/29/2004 at 05:45 ZE2, Rob van der Heij <[EMAIL PROTECTED]>
wrote:

> 2. The z/VM timezone defines the offset to UTC to obtain local time.
> Selecting a different timezone on z/VM is done by hand or through
> magic in the system configuration file

Remembering that the system configuration file is only interpreted at IPL
time.  The system will not automatically switch timezones while it is
running.  CP SET TIMEZONE is required.  (Sometimes this isn't obvious to
everyone.)

> 3. CP commands and some CMS things use local time from CP. Many
> services on z/VM don't care about the sudden time shift.

CMS uses local time for everything.  This is why CMS registers to receive
CP SET TIMEZONE notifications.  It will rediscover the timezone and offset
so that conversions to UTC done by things like NOTE and SENDFILE will be
correct.  CMS file timestamps are local time as returned by CP sans
timezone.  A change in the timezone does not change file timestamps, nor
does a change to the TOD clock.

> 4. Linux uses STCK and gets the LPAR TOD clock which is not affected
> by the timezone on z/VM. It does not make a difference whether you IPL
> Linux or not.

CMS and GCS are the only operating systems to get their time using CP
services.  z/OS and VSE also do not have to be IPLed.

Alan Altmark
z/VM Development
IBM Endicott

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