The DP4 runtime system uses these files in addition to your database:
The system database contains information that is shared across a set of application databases. It contains all the images, help and error messages for the DP4 standard utilities. The list of user names and encrypted passwords with their access levels and language selection is stored on the system database. A set of preferences for display colours, the date and time format, and other setup information is stored for each user.
The input and output devices available on the system are also defined on the system database. This ensures that application databases are device-independent, and that there is only one set of device definitions to maintain. For example, when a report is ready for output, the application may prompt the user to select a printer from a list of those set up on the system database. The output is formatted according to the parameters set up for the printer on the system. The application need not know whether the selected printer is a dot matrix printer, an inkjet or a laser printer.
The licence file is a small file that defines your DP4 licence number and name. This file provides a measure of security against the unauthorised copying of DP4 programs, since it can only be installed from a distribution disk. This file also defines the location of DP4 files, and the console and transaction log settings, as defined during the DP4 setup procedure.
The userdata file defines the characteristics of the workstation you are using. The information in this file tells the DP4 user interface manager if your workstation can display colour, and how the keys on your keyboard are to be translated into ASCII values. This file also stores the default configuration for the colour and preferences on your system.