Abstract: A computer system, having external peripherals, includes an operating system and application packages residing therein. Data exchange logic permits an outside application package (generated by a third party to perform a predefined application function in a general purpose computer environment) to be integrated into the computer system. A data file containing information for making the necessary data available to the outside application package in the computer system is generated off-line. When the outside application package is executing in the computer system and it is desired to obtain the necessary data, a first package is accessed. The first package utilizes information contained in the data file to generate commands to obtain the necessary data. Information of the data file includes source information of the necessary data internal to or external to the computer system. If, however it is desired to output results of the predefined application function, a second package is accessed.