RickDate

RickDate is a compressed date format using a base 36 numeral system to represent a date from the gregorian calendar system, using fewer characters than conventional YYYYMMDD base 10 notation.

RickDate has two forms; a long form using five characters, and a short form using three characters.

In the "long form", each component of the date is represented as a base-36 number, and the three components are concatenated together in Year-Month-Day order (YYYMD). Since the components are concatenated rather than mathematically combined, not all possible base-36 numbers are used; for example, XDQ is not a valid RickDate. The right-most two digits never exceed 12 (C) and 31 (V). The dates are ascii-sortable.

The "short form", using only the last base-36 digit of the year, is preferred for its compactness, although a context is usually needed to determine the intended year. For example, the RickDate format of "September 20, 2006" is 1JQ9K, or Q9K for short.

RickDate was invented in December 1985, and is named after its originator, Rick Wong. [ [http://www.yak.net/kablooey/RickDate.html "RickDate"] by [e-mail], May 22, 1998, retrieved September 14, 2006]

For Comparison:

JimDate is a compressed date format using a base 60 numeral system to represent a date using a minimal number of characters.

JimDate has two forms; a long form using four digits, and a short form using only the three least-significant digits.

The character set comprising a base-60 digit consists of the digits 0-9, the upper case characters A-Y (10-34), and the lower case characters a-y (35-59). A side effect of this character selection is that JimDates are ASCII-sortable.

In the "long form", each component of the date is represented as a base-60 number, and the three components are concatenated together in Year-Month-Day order (YYMD).

The "short form", using only the last base-60 digit of the year, is preferred for its compactness, although a context is sometimes needed to determine the intended year. For example, the JimDate format of "September 20, 2006" is XQ9K, or Q9K for short.

The leading digit X is valid from X011 (January 1, 1980) to XyCV (December 31, 2039). Note that all years ending in 0-9 in JimDate also end 0-9 in decimal.

Because the month and year components never exceed 36 in either system, the short form dates are the same in JimDate and RickDate from January 1, 1980 (011) to December 31, 2014 (YCV), after which JimDate continues with a11 and b11 for New Year's Day in 2015 and 2016 while RickDate proceeds to Z11 in 2015, but wraps back to 011 in 2016.

JimDate was invented in October 1985, as evidenced by the earliest used file suffix .5AM (October 22, 1985) in the originator's archive, and is named after its originator, Jim Walker (not the drummer).

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