Emprise Corporation

Time Zone Server

Excerpt from the MSDN website:

System Time

System time is the current date and time of day.

The system keeps time so that your applications have ready access to accurate time. The system bases system time on coordinated universal time (UTC). UTC-based time is loosely defined as the current date and time of day in Greenwich, England.

Local Time

While the system uses UTC-based time internally, your applications will generally display the local time - the date and time of day for your time zone. Therefore, to ensure correct results, you must be aware of whether a function expects to receive a UTC-based time or a local time, and whether the function returns a UTC-based time or a local time.

The current time-zone settings control how the system converts between UTC and local time. You can retrieve the current time-zone settings by using the GetTimeZoneInformation function. The function copies the result to a TIME_ZONE_INFORMATION structure and returns a value indicating whether local time is currently in standard time or daylight saving time. You can set the time-zone settings by using the SetTimeZoneInformation function.

To retrieve the local time, use the GetLocalTime function. GetLocalTime converts the system time to a local time based on the current time-zone settings and copies the result to a SYSTEMTIME structure. You can set the system time by using the SetLocalTime function. SetLocalTime assumes you have specified a local time and converts to UTC before setting the system time.

Problems associated with mobile networks...

Time Zone Image

When a network moves across time zones it can present special problems to both its administrators and users. As the time zone changes (assuming no user interaction) the local time on a user's workstation will no longer be accurate. Unfortunately, most applications display this local time, causing the network users concern that the computer's time is inaccurate. An inexperienced user may change the computer time instead of the time zone to correct the time display. In Windows NT this has the effect of changing the computer's coordinated universal time (UTC) or System time. This can be further complicated if network login scripts use commands such as NET TIME to automatically set the workstation time.

Changing UTC or System time on a workstation will cause all time stamp functions in both the operating system (such as file time stamps) and applications to be inaccurate. This, depending on the applications being run and the workstation's function, can simply be an annoyance or, in the worst case, a security concern.

Network administrators can and should use the internal NT applications such as time servers and functions or NT policies to ensure the correct UTC time across a network and prevent the average user from being able to modify this information. Additionally, the network administrator should establish a policy to either 1) adjust the workstation time zones as the network moves from one time zone to another or 2) set the network hardware to a static time zone and not adjust it as the network moves across time zones or 3) a combination of both.

Our recommendation is to keep as many workstations as possible and all servers to a static time zone, (preferably GMT), and allow only those workstations that require accurate local time to have the time zone settings dynamically adjusted. In all cases this means that a person or persons with the appropriate access levels has to visit each workstation to set or verify the correct time zone information. This is an inconvenience at best, and therefore may not always be performed correctly or in a timely manner.

The Solution...

Emprise Time Zone Server is designed to eliminate these problems by providing the following

A centralized location for the setting of the time zone on some or all of the network workstations, and Consistent and centrally controlled time zone settings for all network workstations and / or servers without compromising security.

Automatic synchronization of the current time zone across a network

Emprise Time Zone Server provides the ability to adjust the time zones on all of or a subset of the network workstations from a single location.

Emprise Time Zone Server is most useful on networks that travel across time zone, such as those in the maritime or airline industries, but can also be utilized on a stationary network to ensure consistent time zone settings.

Invisible to the end user

Emprise Time Zone Server is designed to minimize user requirements operating in the background to automatically detect when a change has been made to the server's time zone. When detected, this change is transmitted to all workstations within the network that are configured to synchronize with the server. If a workstation is shut down, synchronization is automatically accomplished as soon as it is started.