Abstract: The present invention provides a novel solution to the problem the quickly approaching turn of the century will have on software systems that were not designed to handle dates beyond the year 2000. The present invention is also applicable to any software application where it is desired to virtually change the formatting of any arbitrary item of data. The item of data can come from any type of data source such as data files or computer screen memory. The present invention operates by severing the link between the program conversion process and the data file conversion process. The present invention assumes control each time a converted program reads or writes a record of a data file that has not yet been converted. Converting records during I/O operations, enables a converted program to access an unconverted data file as if it were converted. The invention converts the data fields in a read record to a new format that is implementation specific before passing it on to the program.