Overview

AT THE TIME OF THIS WRITING, date-related programming issues likely to arise in the years 2000 and 2038 are of interest to many system managers and software developers. This appendix discusses some of the problems and common issues, as well as the procedures that can be used to test for and to locate date-related issues within DCL procedures. Many of the testing and review issues discussed in this appendix are general, and are not specific to DCL procedures.

Date-related programming issues and problems are not new in the computer industry. Because of the ways in which programmers can store, retrieve, and utilize dates within programs, it is quite possible for latent date-related bugs to arise in many applications and to occur at various application- or system-specific dates. Programs that have been coded to assume the current century is any particular century contain the classic 2-digit year limitation. When the century changes from 1900 to 2000, for instance, programs that store and retrieve the values of years as 2-character values can incorrectly assume that the year 00 is 1900, and not 2000. Also, applications that have been incorrectly coded to assume that all century years are not leap years can incorrectly handle 2000, which is a leap year.

Applications that manipulate dates 15, 30, or even 40 years in the future will obviously tend to reach date-related limits earlier than applications that manipulate only the current date. Applications that work with future dates include...