Y10K and Beyond
RFC 2550
Network Working Group S. Glassman
Request for Comments: 2550 M. Manasse
Category: Stinkards Track J. Mogul
Compaq Computer Corporation
1 April 1999
Y10K and Beyond
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard of any kind. Distribution of this
memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (1999). All Rights Reserved.
Abstract
As we approach the end of the millennium, much attention has been
paid to the so-called "Y2K" problem. Nearly everyone now regrets the
short-sightedness of the programmers of yore who wrote programs
designed to fail in the year 2000. Unfortunately, the current fixes
for Y2K lead inevitably to a crisis in the year 10,000 when the
programs are again designed to fail.
This specification provides a solution to the "Y10K" problem which
has also been called the "YAK" problem (hex) and the "YXK" problem
(Roman numerals).
1. Introduction, Discussion, and Related Work
Many programs and standards contain, manipulate and maintain dates.
Comparing and sorting dates is a common activity. Many different
formats and standards for dates have been developed and all have been
found wanting.
Early date formats reserved only two digits to represent the year
portion of a date. Programs that use this format make mistakes when
dealing with dates after the year 2000. This is the so-called Y2K
problem.
Glassman, et. al. Informational [Page 1]
RFC 2550 Y10K and Beyond 1 April 1999
The most common fix for the Y2K problem has been to switch to 4-digit
years. This fix covers roughly the next 8,000 years (until the year
9999) by which time, everyone seems convinced that all current
programs will have been retired. This is exactly the faulty logic
and lazy programming practice that led to the current Y2K problem!
Programmers and designers always assume that their code will
eventually disappear, but history suggests that code and programs are
often used well past their intended circumstances.
The 4-digit year leads directly to programs that will fail in the
year 10,000. This proposal addresses the Y10K problem in a general
way that covers the full range of date and time format issues.
1.1 Current approaches
A large number of approaches exist for formatting dates and times.
All of them have limitations. The 2-digit year runs into trouble
next year. The 4-digit year hits the wall in the year 10,000. A
16-bit year runs out in the year 65,536. A 32-bit counter for the
number of seconds since 1970 [UNIX] wraps in 2038. A 32-bit counter
for the number of milli-seconds since booting crashes a Windows (TM)
PC in 49.7 days [Microsoft].
In this specification, we focus on the Y10K problems since they are
most common and a large number of existing standards and protocols
are susceptible to them (section 7). These standards, and new
proposals on their way, will lead to a serious world-wide problem
unless efforts are made now to correct the computing, government, and
business communities.
Already, a small cottage industry is popping up to deal with the Y10K
problem [YUCK]. We encourage these efforts and, in the coming years,
this effort can only grow in size and importance.
1.2 A Fixed Format Y10K Fix
At the time of this writing, only one proposal [Wilborne] directly
deals with the Y10K problem. In that proposal, dates are represented
as decimal numbers with the dates compared numerically. The proposed
format is simply YYYYYMMDD - i.e. 5-digit years.
To allow numerical comparison of dates, this representation requires
a completely fixed representation for the date. There can be no
optional fields, the date resolution is limited to the granularity of
one day, and this solution fails in the year 100,000 (Y100K).
Glassman, et. al. Informational [Page 2]
RFC 2550 Y10K and Beyond 1 April 1999
1.2.2 Limitations of Numerical Comparison
While sufficient for the specific Y10K problem, this solution is
limited. Even if extended for 6-digit years, it fails on 32-bit
systems (and future 32-bit system emulators) after the date
represented by the number 2147481231 (December 31, 214748) leading to
a Y214749 problem. Similarly, 64-bit and 128-bit systems also will
fail, although somewhat later (after December 31, 922,337,203,685,477
and December 31, 17,014,118,346,046,923,173,168,730,371,588,410
respectively).
1.2.3 Granularity Issues
Show full document text