Time

 

Time on a system involves several time concepts, such as time zones, Coordinated Universal Time (UTC), system time, and job time. Each system or partition uses system time. System time is displayed through the time of day system value.

System time is one important time concept. However, you need to understand the various time concepts that play an important role in time management. The following concepts are important concepts that relate to time:

Local system time (system time)

Local system time is determined by applying the system's time zone offset to UTC. The time of day system value displays the local system time. Local system time and system time are used interchangeably.

Local job time

Local job time is determined by applying the job's time zone offset to UTC. To view a job's local date and time, view the Date/Time page of the job's properties.

Coordinated Universal Time

Coordinated Universal Time (UTC) is used to calculate local system time and job time. The offset from UTC is applied to UTC time to calculate the local system time (system time).

Offset from Coordinated Universal Time

Represents the difference in hours and minutes between UTC and the local system time. A negative offset indicates that the time is west of UTC and a positive offset indicates that the time is east of UTC.

Time zone

The time zone settings specify the offset from UTC and whether to observe daylight saving time. Each logical partition on a system can specify a time zone to use.

To combine these time concepts into the various time values associated with a system, examine two systems that use different time zones.

This figure shows two systems in two different time zones. System A is in the Central Standard Time zone and System B is in the Beijing Standard Time zone.

Each system's time values are as follows:

	System A	System B
Local system time	8:00 a.m.	10:00 p.m.
Local job time	8:00 a.m.	10:00 p.m.
Time zone	Central Standard Time	Beijing Standard Time
Offset from UTC	-6:00	+8:00
UTC	2:00 p.m.	2:00 p.m.

 

Parent topic:

Concepts

Related concepts
Coordinated Universal Time Time zone Daylight saving time Managing time zones

Related information
Date and time system values: Time of day