|
|
 |
|
|
|
|
Older system were often designed without the benefits of structured approaches, with the consequence that different programs contain highly individualized solutions. A lack of standards in construction greatly complicates later maintenance. |
|
|
|
|
|
|
|
|
Y2K is exactly the kind of problem that management loathes unplanned, technical, unbudgeted, and major. Some media coverage is already playing the Y2K story from the angle that some programmers decided to take shortcuts in programs. This spin is not accidental. Newsies interview suits, not techies. Management will not accept responsibility for the problem, because it simply cannot afford to do so. Programmers should be prepared to have the dirty end of this stick offered to them, and plan accordingly. |
|
|
|
|
|
|
|
|
Lack of standard date/time routines. A hidden problem revealed, again, by Y2K evaluations is the existence in most shops of multiple date routines. In most cases, the routines do not form an integrated package but rather are a hodgepodge of dozens of functions written to solve specific problems at different times. Often the routines return mutually contradictory results. |
|
|
|
|
|
|
|
|
It cannot be emphasized enough that a "handicraft" approach to date/time routines (or any other standard and critical area) is exceedingly dangerous and completely unnecessary. |
|
|
|
|
|
|
|
|
Y2K has a number of aspects beyond the "my computer thinks it is 1900" problem. Some of these complications are: |
|
|
|
|
|
|
|
|
The DOW The reader who even lightly skims the material in this book will discover that calculation of the day of the week (DOW) for a given date is trivial, given a proper set of date/time tools. It may thus come as something of a shock to learn that many programs use a variety of convoluted algorithms with a date range limited to the last two digits of the year. As a consequence, these algorithms return incorrect results for dates after 31 December 1999. |
|
|
|
|
|
|
|
|
1999 It is important to realize that Y2K begins to have effects before the actual inception of the year 2000. These effects depend upon the application. You may have already encountered canned food with expirations dates like 23 July 1903. In several instances, it has already happened that new products marked with such expiration dates have been scanned during warehouse inventory and automatically flagged for destruction. |
|
|
|
|
|
|
|
|
The year 1999 is significant in several respects. Two of the most critical are: |
|
|
|
|
|
|
|
|
During the 1980s, a common practice was to use a date of "all 9s" for a required expiration date, to indicate that the data was archival and should have no effective expiration date. In 1980, this date may have seemed to be a futuristic concept, but |
|
|
|
|
|