[EMAIL PROTECTED] wrote:
I still do not quite really understand on how the application on
Mainframes log theit times compared to home PCs running UNIX...
I have been told that the TOD clock similar to the RTC/CMOS clock
inside a PC is running in UTC time..I understand that part...Now, the
applications that run on the Mainframe, do those applications log their
times using Local Time thats displayed on the VTAM or MVS consoles or
terminals? Or, do they log their times in UTC time also?
So, I now know that the DBMS applications logs the time in UTC from the
TOD clock. But, do they actually display the LOCAL TIME on the VTAM,
TSO, consoles??
Because like I said, even though my RTC/CMOS clock (which almost the
same as a TOD clock but more accurate)... is set to use UTC. But all of
my system message logs, my system error logs, StarOffice Spreadsheet is
also keeping local time whenever I do the Time Formula in a Spreadsheet
and so forth...These programs are keeping time according to my actual
displayed clock or time thats sits on the desktop.
So are the DBMS applications act the same way by logging or keeping the
ACTUAL DISPLAYED Local Time according to whats on the desktop clocks
(like on the PCs), or do they log in UTC time going by the TOD clock?
In other words, and maybe I am confused by all this still...So in other
words, the DBMS applications are going by UTC according to the TOD
clock...right? But, we cannot see that in reality when they are logged
on the consoles? Am I right? So what the computer operators see a log
by a DBMS application, they actually see the displayed time as being
LOCAL TIME according to the datacenter's current Time Zone...Am I
right?
Same thing with PCs.....My StarOffice database program, and my ssytem
error logs, are going by my actual displayed desktop time which Local
Time (PDT), but the CMOS/RTC clock is keeping time as UTC and because
the fact that it is an INTERNALLY DRIVEN CLOCK...I cannot see that time
actually displayed as UTC in my applications and logs...Am I correct or
wrong..or even partitially correct....?
Thanks.
Under z/OS, z/VM. z/VSE you can ask the system for different times.
It's been years since I have had to do this, so I'm not sure what they
are. But it sort of like asking for UTC/TOD time or localtime. The
application decides. The system log and job logs normally are set to
use local time.
DB2 will use UTC/TOD time however to write to its journals.
Under Linux/Unix I am assuming that you can ask for "hardware time" and
local time.
Plesae note this is NOT a mainframe vs. PC thing. This is a OS vs. OS
thing. Linux acts the same on a Intel based system as it does running
on a mainframe. The underlying hardware is not what really makes the
difference in this case, it is how the OS works in conjuction with the
hardware. To Linux the TOD clock, I am assuming, appears as the
"CMOS/RTC" clock.
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