naggum.no/lugm-time.html 1999-10-11 Erik Naggum Naggum Software Oslo, Norway ABSTRACT The programming language Common Lisp offers a few functions to support the concept of time as humans experience it, including GET-UNIVERSAL-TIME , ENCODE-UNIVERSAL-TIME , DECODE-UNIVERSAL-TIME , and GET-DECODED-TIME . These functions assume the existence of a timezone and a daylight saving time regime, such that they can support the usual expression of time in the environment in which a small number of real-life applications run. The majority of applications, however, need more support to be able to read and write dates and times, calculate with time, schedule events at specific clock times daily, and work with several time zones and daylight saving time regimes. This paper discusses some of the problems inherent in processing time suitable to humans and describes a solution employed by the autho...