[sdkmvx]

Are you sure?

Today is July 31, 2018 in the United States, which adopted the Gregorian calender per the act of British parliament entitled "An Act for Regulating the Commencement of the Year; and for Correcting the Calendar now in Use" (24 Geo. 2 c. 23) by skipping September 3-13, 1752 (obviously this was prior to the American revolution).

In the Julian calendar, there are leap days every four years. In the Gregorian calendar, there are leap years every four years except every 100 years except every 400 years. That is, 2000 and 2004 are leap years, but 1900 is not a leap year.

Since 100, 200, 300, 500, 600, 700, 900, 1000, 1100, 1300, 1400, 1500, 1700, 1800, and 1900 were leap years in the Julian calendar but not the Gregorian calendar, one must subtract 15 days to get to the Gregorian date to get the Julian date.

Today is July 18, 2018 in the Julian calendar.

The Soviet Union adopted the Gregorian calendar in 1918 by skipping February 1-13. They were the last. This is why the famous February revolution took place in March and why the October revolution took place in November. (Though I noticed Reuters announced it had been 100 years last year on the wrong day.)

Mainframes are weird, but I really doubt they don't use the Gregorian calendar whatever the text on the screen says.