+(defconstant +posix-epoch+
+ (encode-universal-time 0 0 0 1 1 1970 0))
+
+(defun posix-time-to-utime (time)
+ (+ time +posix-epoch+))
+
+;;;; Daylight Saving Time calculations
+
+;; Daylight Saving Time begins for most of the United States at 2
+;; a.m. on the first Sunday of April. Time reverts to standard time at
+;; 2 a.m. on the last Sunday of October. In the U.S., each time zone
+;; switches at a different time.
+
+;; In the European Union, Summer Time begins and ends at 1 am
+;; Universal Time (Greenwich Mean Time). It starts the last Sunday in
+;; March, and ends the last Sunday in October. In the EU, all time
+;; zones change at the same moment.
+
+;; Spring forward, Fall back
+;; During DST, clocks are turned forward an hour, effectively moving
+;; an hour of daylight from the morning to the evening.
+
+;; United States European Union
+
+;; Year DST Begins DST Ends Summertime Summertime
+;; at 2 a.m. at 2 a.m. period begins period ends
+;; at 1 a.m. UT at 1 a.m. UT
+;; ----------------------------------------------------------
+;; 2000 April 2 October 29 March 26 October 29
+;; 2001 April 1 October 28 March 25 October 28
+;; 2002 April 7 October 27 March 31 October 27
+;; 2003 April 6 October 26 March 30 October 26
+;; 2004 April 4 October 31 March 28 October 31
+;; 2005 April 3 October 30 March 27 October 30
+;; 2006 April 2 October 29 March 26 October 29
+;; 2007 April 1 October 28 March 25 October 28
+;; 2008 April 6 October 26 March 30 October 26
+
+