Efficient Timestamp Input and Output

this paper we provide efficient algorithms for converting between timestamp values that signify some number of seconds from an arbitrary origin, and character strings specifying Gregorian dates, such as `January 1, 1993'. We give several algorithms that explore a range of time and space trade-offs. Unlike previous algorithms, those discussed here have a constant time cost over a greatly extended range of timestamp values. These algorithms are especially useful in operating systems and in database management system