At work I save a lot of files with dates in them without the solidi, virgules, slashes, as such: 20100509 for today. Sorts and saves in chronological order. QED.
I learned the tented ones and cross-dashed sevens in my 2 years in France with the navy (US). I used the dashed 7’s for years when I got back until someone thought it was abackwards f and messed up my address on something important. They used 10f instead of 107 and I didn’t get the mail.
The Japanese do (and I imagine that they’re not alone in E Asia).
The point I was trying to make is, if you see 2010/02/03, you immediately know it’s February 3rd, 2010, because nobody writes March 2, 2010 as 2010/02/03.
I’ve dealt with this issue many times and the only way I’ve found to avoid confusion is to always use the name of the month and not a number. In the computer languages I use, the correct name of the month is automatically selected based on the regional settings of the computer. Date/Time is stored internally as double precision floating point numbers.
Except the North Koreans. It is more logical, when you think of it; largest unit first, just as with Arabic numerals. I use it on my site, so there is no mistaking the date of a post.
I’ve seen Europeans use Roman numerals for the month; for example today is 9 V 2010. The protocol looks very old fashioned to my eyes.
It’s the international standard (ISO 8601) for date notation. Lots of people and organisations (including my own workplace) use it for the same reason you do - so that filenames sorted by alphabetical order will also be in chronological order.
If you really want to confuse someone use Julian Dates.
May 9 2010 is JD 2455325.50000
Computers use it to calculate the number of days between two dates.
you charged an item on March 2, 2010 JD 2455257.50000
the account is currently 68 days past due
a handy JD converter
http://aa.usno.navy.mil/data/docs/JulianDate.php
Ugh. Confusion with US (vs UK/European) date formats still causes some horrible problems in even quite mainstream applications. Even if you have all of the regional options correctly set for UK dates, and you have date fields formatted as a short date in dd/mm/yy format, a mailmerge from Excel to Word will still assume it’s looking at an American date value, unless a day value greater than 12 forces its hand. Same thing often happens if you try to import a CSV to Excel, and so on.
Microsoft Office is, of course, a product of US origin, but this should not excuse it ignoring the regional settings.
I agree - settling on yyyy/mm/dd (hh:nn:ss) would be both logical and less ambiguous. I too use this if I’m writing a timestamp into a filename, as it automatically creates a sorting order, even if the true date values attached to the file are changed by later opening/modification.
I am! That’s pretty much how I format dates, now. Either that, or 1999-Dec-31.
Here in Mexico, I often see dates written like this: 31/XII/99. I think because they’re in this weird soup-bowl mix of so many different cultures and numbering systems (EU investment, NA investment, Asia-Pacific investment) that it helps keep things clear regardless of who happens to be reading the date. Or maybe it’s for some other reason; I don’t know.
On the other hand, 12/31/1999 makes better sense than 31.12.1999 when you’re trying to read it out loud since people typically will say, “December 31st, 1999” when reading this date rather than “the 31st day of December, 1999.”
When speaking about a date, people typically mention the month first, the day of the month second, and then (if mentioning it at all), the year. It’s not unheard of to say something like “Remember remember the 5th of November” but it is an atypical (partly poetic, partly awkward, partly archaic) way of speaking.
In the US, people write “12/31/1999” and say “December 31st, 1999”.
In Ireland, people write “31/12/1999” and say “31st of December, 1999”.
Yeah, you’re just being a bit provincial there, Simon - in the UK, people most often say 'the 31st of December" and it doesn’t feel archaic at all to them (maybe it sounds it to you, but that’s just because US and British Englishes have diverged - ‘gotten’ sounds archaic to folks in the UK, for example).
We say our dates the way we write them. And it seems perfectly normal to do so.
If we are that worried about how the file system will sort dates in a filename, shouldn’t we also agree that the date fields should be separated by hyphens and not slashes? Slashes aren’t legal in Windows file names.
I’m not really all that interested in establishing a standard for this - I just do it out of expediency in some situations where my applications have to archive files without collision in the name - sortability in the name is incidentally useful sometimes. I tend not to use separators at all when I do this, so it’s yyyymmddhhnnss (and I pad with zeroes so that 9 sorts before 10.
I only tried using slashes once, and of course it didn’t work.
Canada for example, uses the exact same date system as the USA - except for the Canadian government, where some branches still use DD-MM-YYYY; so Microsoft thinks that is how we talk aboot dates, and so messes up dates for anyone who honestly tells their PC it is in Canada.
As mentioned, there’s the odd way fo writing one, which results in the odd way of crossing the severn so you know it is not a one.
Then the different countries have different other punctuation, not just the decimal notation. IIRC the French and most Europeans use dashes instead of quotes for dialog; the Spanish have the inverted question mark and exclamation mark around sentences. Not to mention all those weird punctuation symbols over or under letters, which we English speakers thankfully think are passé.
I guess it doesn’t matter what each locale did for its grammar, punctuation, or orthography until we try to make one computer system do it all.
I was always taught in maths class (in the UK) that 100,000 means 100 000, but we leave out the comma in case it’s mistaken for a decimal point.
Actually, in my experience, Canada uses a mixture of date styles in English.
I have to fill in the date boxes on my cheques as YYYYMMDD. The forms I got from the provincial Ministry of Housing use DD/MM/YYYY. My federal tax forms use YYYYMMDD. The work order for my internet install used YY/MM/DD.
And recepts are even more of a mix. The receipt from my last purchase at Tim-br Mart uses YYYY/MM/DD. My last purchase at the office supplies store? MM-DD-YYYY. The book store? The train station? YYYY/MM/DD on the debit receipt and DD Mon YYYY on the actual ticket (month name spelled out to 3 letters). The grocery store? MM/DD/YYYY. Big-box electronics store? MM/DD/YYYY. Other electronics store? Mon-DD-YYYY.
A surprising number of places still use a 2-digit year! I have had more than one receipt with a date like 05/04/06, which is completely ambiguious. I’ll admit that, afterr a survay of receipts I happen to have handy, smaller businesses tend to use some variation of MM/DD/YYYY, but that is by no means a given.
We need to standardize, and I personally am standardizing on YYYYMMDD.
Maybe Quebec is saner…
Nobody in the real world writes the dates starting with the year first, either. 
And for that matter, I’d still read “2010/02/03” and “March 2nd, 2010”- 2010, Second Day of the Third Month.
IMHO, starting with the year is silly for everyday use because everyone knows what year it is (except for coma patients and people who’ve fallen through wormholes in the time-space continuum), and so writing “2010/Mar/02” sounds like the sort of thing a medieval monk would do: “In the year of our Lord Two Thousand and Ten, In the Month of March, Upon The Second Day”.
I’m not aware of any computer or operating system that uses astronomy’s Julian dates for its time-keeping standard. The Julian date system counts days since January 1, 4713 BC. Most computers instead count in seconds, or fractions of a second, and the zero point is much closer to our own time — usually in the 20th century. (But see here for an interesting table.)
The Hungarians do.