The following list has been provided to assist you in determining the type of file according to its extension.
.BAK The extension ".BAK" indicates that the file is a backup file. This extension is used by VTS and a wide variety of other software packages.
.DAT The extension ".DAT" is a VTS naming convention that indicates a data file. Data files in VTS may contain logged data for a tag, or a historical record of alarm events in VTS.
.DB The extension ".DB" is a VTS naming convention that indicates a database file created by a DBSystem call. Two common VTS files using the extension ".DB" are the "Alarms.DB" file (housing a record of alarm events); and the "Config.DB" configuration database (that stores locking information for networked applications).
.LDB The extension ".LDB" is used for ODBC files, indicating a lock on a Microsoft Access database.
.LOG The extension ".LOG" is a VTS naming convention that indicates a log file containing a record of the .DAT file names for logged data for a tag.
.MDB The extension ".MDB" indicates a Microsoft Database file. An example of a VTS file using the .MDB extension is "Points.mdb" tag properties database.
.OLD The extension ".OLD" is a VTS naming convention that indicates a file related to the redo function. .OLD files are used by the Undo/Redo Manager.
.UDO The extension ".UDO" is a VTS naming convention that indicates a file related to the undo function. .UDO files are used by the Undo/Redo Manager.
.VAL The extension ".VAL" is a VTS naming convention that indicates a file containing persistent values for a module.
.WIF The extension ".WIF" is a VTS naming convention that indicates an information file used by VTS to store and extract information about an application. ".WIF" stands for "WEB Information File"; WEB was the former name for VTS.
.XLS The extension ".XLS" indicates an Excel database file.
Where "VTS naming convention" is indicated in the above table, it should be noted that these extensions are naming conventions to help identify groups of files generated by a specific function. For example, a DBSystem call can log to a file with any extension - it does not generate the extension automatically; in our code, though, if we use a DBSystem call, we log it to a file with a .DB extension (i.e. "Config.db", or "Alarms.DB").
This knowledge may be useful in situations where a specific text file (i.e. ".txt") in a remote or networked application keeps reverting to "read-only". In such a situation, you may use the SetFileAttribs function to toggle off the "read-only" setting each time you wish to modify the file, or you may simply re-name the file using one of the VTS extensions (for example, ".DAT").
In using SetFileAttribs to toggle the read-only attribute, the file will continue to be propagated across the network, but each workstation running the application may end up with different copies; changing the extension can overcome such a situation.