If you need to know whether DST was in effect for a date in the past on windows, you’ll probably get grumpy. With the DST change this year, Microsoft changed the dates at which it starts and finishes DST. That’s great, and makes sense. What is harder to understand, however, is why the Microsoft date routines also changed the DST handling for years prior. Win32 APIs can no longer accurately tell you what time it was on Nov 1, 2006.
Raymond Chen writes it up pretty well. He has many excuses reasons for why Microsoft didn’t get it right. There is no doubt that time management is a pain in the neck and annoying. But, at the end of the day, even the free operating systems do get it right. Linux can tell you just fine.