data point: For variables keeping history, the value of the variable and its corresponding collection times.
data seeking: The attempt to obtain a new current value for a variable.
data server: The source of values for a variable, or the destination where G2 can send data with the
datatype: See type.
dedicated license: One type of G2 license for Telewindows. In a dedicated Telewindows environment, each license is authorized for a specific level of access to the server.
default attribute: For a user-defined class U and its superior classes that define more than one attribute with the same name, the version of the attribute defined by the class closest to class U on U's class inheritance path.
default language: The language translation item (or the symbol
english) that G2 uses to display the names of menus and menu choice text (and for some languages, a custom Text Editor interface) in the G2 developer's environment. You set the current KB's default language only with the
-default-languagecommand line option. Contrast with current language.
default scale: By default, a new workspace's current scale is the normalized scale for the G2 process, which G2 determines by calculating the ratio of workspace units per pixel of resolution on your computer's display device.
default value: The value that an attribute other than a variable or parameter value has on instantiation. This value persists until something changes it. Resetting G2 does not change it. See also initial value.
dependent variable: A simulated variable whose value is not based on the variable's previous value. A dependent variable does not require an initial value.
depth-first backward chaining: For a set of rules that can conclude a new value for a particular variable, the activity where G2 invokes those rules in order of precedence, according to the
Depth-first-backward-chaining-precedenceattribute of each rule in the set. Contrast with breadth-first backward chaining.
direct superior class: The class or classes from which a class inherits directly. A class also inherits indirectly from all the superior classes of its direct superior class or classes.
directly-requires: The relationship between two modules, where the knowledge in one module depends upon the knowledge in the other. Before loading or merging the modularized KB file F that contains module M, G2 first loads each modularized KB file that contains a module that module M directly requires, then loads the modularized KB file F.
display: System-defined classes whose instances are items that show the value of a parameter, variable, or expression. Readout tables, dials, meters, graphs, trend charts, and freeform tables are displays.
duplicate definitions: Duplicate items that are class definitions. Contrast with identical definitions.
duplicate methods: Methods that have the same name, and are defined on the same class, but differ in the number of arguments each method takes.
duplicate items: Items that have the same name, whether or not the items have the same type or are functionally equivalent. Contrast with identical items.