Thread:Translating talk:NOCC/Date and time notation on NOCC

The default date format on NOCC is Y-m-d which I understand to mean Y=year, m=month and d=day. The default time format is I-M-p. What do these letters stand for? And what software uses this notation? I have googled this but without success. My aim is to write this up on FAQ and on the relevant NOCC message.