Armaggik, забыл что то ПО писалось на билдере.
"The integral part of a TDateTime value is the number of days that have passed since 12/30/1899. The fractional part of a TDateTime value is fraction of a 24 hour day that has elapsed.
Following are some examples of TDateTime values and their corresponding dates and times:
0 12/30/1899 12:00 am
2.75 1/1/1900 6:00 pm
-1.25 12/29/1899 6:00 am
35065 1/1/1996 12:00 am"
или по-русски:
http://www.sources.ru/builder/faq/021.html