Two-digit hybrid radix year numbers for year 2000 and beyond

A method for using 2 digit "hybrid radix" numeric fields for inputting, generating, storing, processing, and outputting year numbers ranging from 1900 to 2059 in a data processing system, comprising the steps of:

• a) representing a 4 digit decimal year number with a biased 2 digit hybrid radix year number, with a hexadecimal most significant digit and a decimal least significant digit, and;
• b) inputting the higher digit of a 2 digit hybrid radix year number in hexadecimal, from an input device capable of entering 2 digit hybrid radix numbers, and storing the digit in the most significant digit position of a 2 digit numeric field in hexadecimal, and inputting the lower digit of the number in decimal, and storing the digit in the least significant digit position of said 2 digit numeric field, and optionally;
• b') whenever necessary, generating such a 2 digit hybrid radix year number, and storing the generated number in a 2 digit numeric field, and optionally;
• c) whenever a computational operation is to be applied to a stored 2 digit hybrid radix number, applying hexadecimal arithmetic rules to the most significant digit, and applying decimal arithmetic rules to the least significant digit, and;
• c') alternatively, whenever a computational operation is to be applied to a stored 2 digit hybrid radix number, expanding the number into 3 digit decimal first, then applying decimal arithmetic rules to all the digits and converting the result back into 2 digit, and optionally;
• d) whenever necessary, outputting the stored 2 digit hybrid radix year number to an output device capable of displaying or printing 2 digit hybrid radix numbers, with the higher digit in hexadecimal and the lower digit in decimal, and;
• e) providing a central processor to carry out said operations,
• whereby a compatibility with the 2 digit pure decimal year numbers used in the existing data files, database records, software, and user interface, can be maintained after year 1999.