Abstract: A data transmission system includes a data storage medium that has a segmented memory that stores an application directory that has an attribute for identifying an application area of the data storage medium and has a logical application number which is associated with an executable application and which is determinately specified by the attribute. The logical application number is used as an index within the application directory. The data transmission system further includes a read/write unit that stores the attribute and the logical application number of the application. The read/write unit is configured to execute the application by using the logical application number in the application directory for indexing and finding a start address for a sector of the memory which stores the executable application.