On Fri, May 20, 2011 at 3:48 PM, Harold Hallikainen wrote: > >> The tzdata package in Linux is approximately 5.8Mb, and that is >> compiled binary data! Of course, it contains a history of all timezone >> changes that have occurred, so it could probably be pared down to >> contain the current data only. But I think it would still be a lot of >> data. >> >> > > I wonder about the code to interpret that data. If I could let the > installer describe somehow (a job regular expressions or something equall= y > cryptic) when the changes occur. I could then use the timestamp to figure > out whether to advance the displayed time or not. > > I could probably use a spreadsheet to generate my own table for a variety > of time zones. I'd generate a text file that's an array of 32 bit numbers > (time stamps) for, perhaps, the next 50 or 100 years. I'd get the current > time stamp, then search the table until I find the time that is just belo= w > the current time. If the lsb is zero, we're on standard time. If it's one= , > we're on DST. Since the product has an SD card, I could have all this dat= a > out there and load with just the appropriate data. You can't predict DST changes in advance without a crystal ball. For example, the Energy Policy Act of 2005 implemented changes in DST starting in 2007 calendar year: http://en.wikipedia.org/wiki/Energy_Policy_Act_of_2005#Change_to_daylight_s= aving_time --=20 Mark Rages, Engineer Midwest Telecine LLC markrages@midwesttelecine.com --=20 http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist .