[TUHS] primary sources for the 1966 Multics ASCII cutover as the first "Flag Day"?

[Adam Sampson]

Royce Williams <royce at techsolvency.com> writes:

> 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.

You can see the early history of the Jargon File through the SAIL copy,
which is AIWORD.RF in this directory:
  https://www.saildart.org/[UP,DOC]/

The FLAG DAY entry was added between 1977-02-01 and 1977-03-11, and
initially read:

| FLAG DAY [from a bit of Multics history involving a change in the
|    ASCII character set originally scheduled for June 14, 1966]
|    n. A software change which is neither forward nor backward
|    compatible, and which is costly to make and costly to revert.
|    "Can we install that without causing a flag day for all users?"

That appears to be the earliest instance of the term in the public
SAILDART files. The next I could see is in a mail message from Mark
Crispin on 1977-10-01. (He must have liked the term; in the utzoo Usenet
archive, quite a lot of the early examples are from him too!)

-- 
Adam Sampson <ats at offog.org>                         <http://offog.org/>