The new second base in dating

Redundant Information ................................. It is defined as the duration of 9,192,631,770 cycles of microwave light absorbed or emitted by the hyperfine transition of cesium-133 atoms in their ground state undisturbed by external fields. However, see also the restrictions in section 5.7 and Appendix D for how leap seconds are denoted within minutes. A leap year is a year whose number is divisible by four an integral number of times, except that if it is a centennial year (i.e.

Simplicity ............................................ second A basic unit of measurement of time in the International System of Units. leap year In the Gregorian calendar, a year which has 366 days.

the new second base in dating-25

Please refer to the current edition of the "Internet Official Protocol Standards" (STD 1) for the standardization state and status of this protocol. Copyright Notice Copyright (C) The Internet Society (2002). Abstract This document defines a date and time format for use in Internet protocols that is a profile of the ISO 8601 standard for representation of dates and times using the Gregorian calendar. Introduction ............................................ The problems with two digit years amply demonstrate why all dates and times used in Internet protocols MUST be fully qualified.

Two Digit Years ......................................... o It is possible that a program using two digit years will represent years after 1999 as ":0", ":1", ... This occurs if the program simply subtracts 1900 from the year and adds the decade to the US-ASCII character zero.

Local Time .............................................. Programs wishing to robustly deal with dates generated by such broken software may add 1900 to three digit years.

Date and Time format .................................... Internet Date/Time Format The date format defined in section 5 of this document.

Ordering .............................................. Email Date/Time Format The date/time format used by Internet Mail as defined by RFC 2822 [IMAIL-UPDATE].

Human Readability ..................................... ABNF Augmented Backus-Naur Form, a format used to represent permissible strings in a protocol or language, as defined in [ABNF].

Rarely Used Options ................................... divisible by one hundred) it shall also be divisible by four hundred an integral number of times.

Coordinated Universal Time (UTC) ...................... This occurs if the program simply subtracts 1900 from the year and doesn't check the number of digits.

Local Offsets ......................................... The following requirements are to address the problems of ambiguity of 2-digit years: o Internet Protocols MUST generate four digit years in dates. If a 2-digit year is received, it should be accepted ONLY if an incorrect interpretation will not cause a protocol or processing failure (e.g. o It is possible that a program using two digit years will represent years after 1999 as three digits.

Unknown Local Offset Convention ....................... Z A suffix which, when applied to a time, denotes a UTC offset of ; often spoken "Zulu" from the ICAO phonetic alphabet representation of the letter "Z".

Unqualified Local Time ................................ Timestamp This term is used in this document to refer to an unambiguous representation of some instant in time.