Core File Transference - GDI.wif

The first of the four core files transferred from server to client during a Get From Server operation is the application's GDI.wif file. The GDI.wif file is used by VTS to identify a directory on your hard drive as being an application directory; therefore you can expect to find one GDI.wif file in each of your application directories.

The GDI.wif file consists of the following information (in order by line):

1.  The name of the application;

2.  The path of the parent application layer relative to the VTS installation or product directory (i.e. the path of the application directory (within the VTS installation directory) upon which this application is based. If this application is based on the VTS layer, the second line will read, "VTS\". If this application is based on another VTS application, such as a custom OEM layer, the second line will display the name of the custom OEM layer's directory, as shown in the example below. If this application is a script application, the second line is left blank.);

3.  A globally unique identifier (GUID) for the application (see details below);

4.  The name of the .RUN file for the compiled application (typically "System"); and

5.  The name of the ODBC data source used to connect to the application's tag properties database (Points.mdb) and replica tag database (SCT.MDB).  Prior to VTS 8.0, the ODBC name would normally be the same as the application’s name.  If using a file DSN (the default after VTS 8.0), you must indicate that this is the case by putting “fileDSN=” in front of the name

Example:

fileDSN=c:\vts\Access.DSN;DBQ=c:\vts\app\Points.MDB;

 

This can be shortened with two special symbols:  ^V indicates the VTS directory and ^A indicates the application directory. 

If this application is a script application, it does not require an ODBC data source, and the fifth line is therefore blank.

 

An example of the information to be found in a typical GDI.wif file for a standard, layered application is displayed below.

The second example below displays the contents of a typical GDI.wif file that might be found in the application directory for a typical script application.

Note that the second and fifth lines remain blank for the script application's GDI.wif file; if you are in a position to delete data from a GDI.wif file (for example, in the event that you encounter duplicate GUIDS – see "VTS Developer's Guide: 3: The VTS Application Manager: Duplicate Globally Unique Identifiers (GUIDS)"), it is very important that a blank line be left in place of the deleted data, rather than deleting the line completely, as reflected in the example above.

GDI.wif files are text files that can be opened and modified using any text editor (such as Notepad, WordPad or UltraEdit).

Globally Unique Identifier (GUID)

As mentioned above, a Globally Unique Identifier or "GUID" exists within the GDI.wif file for each VTS application. This GUID is assigned to the application when it is initially created. The GUID helps VTS to distinguish between different applications.

No two GUIDs are assigned alike, although it is possible that two different versions of the same application can reside on one workstation (e.g. in the event that two different versions of the same application exist on the same workstation), thereby causing VTS to alert you to the presence of duplicate GUIDs. Instructions on remedying this situation can be found in "VTS Developer's Guide: 3: The VTS Application Manager: Duplicate Globally Unique Identifiers (GUIDS)".