(International) Institute of Electrical and Electronics Engineers

(or something to that effect)

In the glossary? It must be some English standard. I can’t find it at wikipedia or a quick search online. I don’t remember who added that bit to the ruleset. What does FLA and TLA stand for?

Well… TLA’s are three letter acronyms.

aha… of course. I’m used to seeing ‘FLA’ as the extension for a Flash file.

I prefer ATLA’s. It is itself an ATLA, which is no more than an augmented three-letter acronym.

The IEEE (pronounced “eye triple-eee” is the international professional association for electrical engineers. 

The British version is the IEE (I do not kid).  In the engineering profession (and in uni) you hear ‘ieee standard xy’ all the bloody time, even if you’re not an EE.

The electrical engineers are by far the most organised internationally of any of the major engineering fields.

http://www.ieee.org

I think the most direct answer to the underlying question you are likely asking is:

http://standards.ieee.org/guides/style/section5.html

;P As Excalibur notes, the IEEE is in charge of maintaining a body of standards. These standards include things like protocol and language specifications. Those specifications have to deal with cases of “when the program receives a B, it shall reply with A”.

Ok, here I break down into mostly incoherant rambling. I should really have not typed this and just gone to bed instead (it’s 6:30am here ;P). This may be funny for someone to read, so I’m going to leave it, hehe:

But maybe it doesn’t have to. Maybe it “may” reply with A. Technically it “can” reply with D (I mean, who’s going to stop it?), but that isn’t allowed, so there’s always some way to detect that this has occured and deal with it. If for some reason it _is_ technically impossible for something to not occur, then “must” is called for. Normally people and programs have choices in these matters, so “must” hardly ever comes up. People who write specifications, however, sometimes forget that, and write “must” anyway, which can cause confusion to someone who’s reading it and expecting that that “must” occur, and then someone doesn’t follow the standard, as they “can” do otherwise (even though they “may” not), and doesn’t.