I see the Wikipedia "Flag day (computing)" [1] article references two
semi-different ESR sources [2,3] to support the claim:
This systems terminology originates from a major
change in the Multics
operating system's definition of ASCII, which was
scheduled for the United
States holiday, Flag Day, on June 14, 1966.
I don't doubt the validity, but I'm looking for other "citation
worthy"
sources that supplement this claim --- ideally that predate the ESR ones,
so that they are unambiguously independent.
1.
https://en.wikipedia.org/wiki/Flag_day_(computing)
2.
http://www.catb.org/jargon/html/F/flag-day.html
3. *The New Hacker's Dictionary*
<https://books.google.com/books?id=g80P_4v4QbIC&pg=PA192>pp. 192–
--
Royce Williams
Tech Solvency