I was just reading an article about the new U.S. Energy Bill that intends to extend Daylight Savings Time an additional month (starting in 2007). I wonder what the impact of this is on the Computer Science front. There has not been any chatter on my normally read blogs, but perhaps there will be soon. I have no facts to back up my theory here, but lets play along with my conspiracy theory and possibly learn something about static and dynamic linking of DLLs.
Think about this from the Microsoft C/C++ developer perspective: the date functions are implemented in the C standard library, MSVCRT.DLL (or its post VC6 brethren MSVC*.dll). Lets assume (although I am guessing) that the "rules" for the current daylight savings time are implemented in this same DLL (NOTE: Please see comments). One of these functions is called mktime(). Let me quote from MSDN:
When specifying a tm structure time, set the tm_isdst field to 0 to indicate that standard time is in effect, or to a value greater than 0 to indicate that daylight savings time is in effect, or to a value less than zero to have the C run-time library code compute whether standard time or daylight savings time is in effect. (The C run-time library assumes the United States's rules for implementing the calculation of Daylight Saving Time).So if we developers assumed that the runtime would take care of conversions for us, and we statically linked to the library, we may have to recompile against a newer link library (with the revised code) for our applications to continue working if this change actually happens. On the other hand, had the developer dynamically linked to this DLL and not copied the pre-dst-updated MSVCRT.DLL to the application folder or application current directory (Remember that in Windows Server 2003 and possibly Windows XP the rules have changed), the DLL can be updated once in the system32 directory (perhaps through Windows Update) and our preexisting applications will be none the wiser and work just fine with the change.
This is more food for thought on the debate of static vs. dynamic linking that could help sway some developers into a different line of thought - I prefer dynamic linking, but in some cases for some applications I do not practice what I preach. For the installation folks, please read the previous link (and the comments - good stuff there on merge modules) - this is why you need to be sure that you are following proper version replacement and marking shared DLL's as shared - otherwise you can cause grief for other applications or your own.
[UPDATE: 10/4/2005 - fix formatting and errant character]