Programmers’ Day (Russian: День программи́ста) is an international professional holiday, recognized in many technology companies and programming firms, that is celebrated on the 256th (hexadecimal 100th or (2^8)th) day of each year (September 13 during common years and on September 12 in leap years). It is also officially recognized in Russia and observed in several other countries, including China, Croatia, Guatemala, France, India, New Zealand, Poland, Slovenia, the United Kingdom, and the United States.
The number 256 (28) was chosen because it is the number of distinct values that can be represented with an eight-bit byte, a value well-known to programmers. 256 is the highest power of two that is less than 365, the number of days in a common year.
This particular day was proposed by Valentin Balt, an employee of Parallel Technologies web design company. As early as 2002, he tried to gather signatures for a petition to the government of Russia to recognize the day as the official programmers’ day.
On July 24, 2009, the Ministry of Mass Communications of Russia issued a draft of an executive order on a new professional holiday, Programmers’ Day.
On September 11, 2009, President of Russia Dmitry Medvedev signed the decree.