Stability of "Created" and "Modified" dates


My question is really about OS X but I ask it because of a possible use for DevonThink Pro.

I’m wondering just how stable the “Created” and “Modified” dates are in the OS X Finder?

In the past I have relied on these dates in Windows XP to discover that unfortunately they all became swept away.

With the Classic Mac OS I have had “Created” and “Modified” dates changing to 1904 when the PRAM battery died. At least I think that’s what happened, it was a long time ago!

So, in OS X are these dates as secure as the data within the file?

The reason I ask is that I’m considering using DevonThink Pro for keeping a log of a very important project which runs over the next four years. The dates and times of the entries are important to me. In the past I have used MacJournal for this. MacJournal keeps dates and times for the entries in its own metadata whereas DevonThink Pro seems to rely on the “Created” and “Modified” dates of OS X.

Inputting data to DevonThink Pro is easier and searching the data within DevonThink Pro is very much better than MacJournal, but I worry about the stability of the “Created” and Modifed" dates.

Thank you!

Umm… Where’d you get that? A DTPO database maintains it’s own copies of date created, modified and added.


Those dates aren’t in Finder, they’re in the filesystem.

It really depends on how you define “stable” and “secure”, and how files will be managed. In general, file creation times are less likely to be unintentionally/unexpectedly changed than file modification times.

Only Date Added is unique to documents in DT databases. Date Created and Date Modified are associated with corresponding files in the filesystem. Try this:

Add a document to DT, change its file in an external app, and notice Date Modified for its DT document has been updated. There’s no separate Date Modified in DT.

You might want to check the DTPO database fields via Applescript to verify your assertion…


I’m not sure how to do that but my guess is the creation/modification date values are being read from and written to the filesystem.

Actually, upon further testing it appears DT does store the dates in its database and only reads/writes them to/from the filesystem in certain cases. So I’ll retract my “no separate Date Modified” statement but am sure it does some date mirroring between the database document and external file values. If not, how else would DT notice when a document’s modification time changes when the corresponding file is changed without using DT?

Edit: Just noticed these console messages correlating with when a DT file was externally modified:

Aug 21 17:26:45 halo DEVONthink Pro[20216]: Received 1 fsevents
Aug 21 17:26:45 halo DEVONthink Pro[20216]: /Users/sjk/Library/Application Support/DEVONthink Pro 2/Inbox.dtBase2/Files.noindex/jpg/0/ => ./jpg/0, Flags 0000
Aug 21 17:26:45 halo DEVONthink Pro[20216]: Synchronizing 1 items

Thank you for the interesting discussion on creation, modified and added dates in DevonThink Pro.

My feeling is that I’m best sticking with MacJournal for my logging as I feel more secure with its date system and it offers a nice interface for modifying dates of entries.

However I do use DevonThink for many other things, not least 90% of the research materials for my project.

I understand the concern about stability of date information in Windows, and I once had date shifts of files way back in System 7, probably as the result of a rogue extension.

But I have had zero problems with loss of date information in my DEVONthink databases, which hold files more than 11 years old that were captured into DT about 6 years ago, up to files captured today. There are no Creation Dates or Modification Dates that fall outside the range of dates that I know to be valid, among many tens of thousands of files.

I’ve always had a habit of keeping some groups sorted by Creation Date. For example, I keep logs of task progress for some projects. At a glance I could tell if there had been any changes in the order of those progress logs. A check of 10 samples over a 5 year span found no discrepancies.

When I create a note I’m in the habit of including the date in the body of the note. I checked at random some 12 notes over dating back from the recent past to 5 years ago, and in every case the Creation Date and the internal date were the same.

I’m probably a bit paranoid. I do things like taking a screenshot of a page of a History display and years later check to see if all those files are still there in the same sort order (Creation Date). I’ve got some databases that contain historical records that I don’t want to lose (such as a financial database), which is why I use this check procedure. I don’t see changes other than the case of an added file with an old Creation Date, which does happen once in a while because I’ve found and added such a file. :slight_smile:

In other words, I’ve seen no evidence of lack of stability of date information in my DEVONthink databases.

But when p a t r i c k started this thread, I decided I had better do some checks. No problems found. Paranoia subsides. :slight_smile:

One thing to check, if it might be important to you, is if files of exported MacJournal entries retain the same dates as the entries. Exported DT documents (at least in methods I’ve tested) are basically just cloned copies of associated files from its database so dates and other file attributes are preserved.

My experience is that DT generally/normally/usually preserves dates when importing/exporting, which I’ve always preferred and appreciated. Dates of exported files from other “database” apps will have the export date instead of dates from their counterpart entries, while dates of entries of imported files will have the import date. To me those date changes/differences imply the content has changed, which it hasn’t.


Thanks to Bill_DeVille and sjk for your additional comments.

MacJournal exports entries with creation and modification dates of the files intact. In MacJournal there is an additional date which is the date you actually give to the entry. During export you can include this date in the file itself at the top, actually its rather neat. In my case 99% of the time the creation date and the date for the entry in MacJournal are the same as they are created at the same time.

I’m very glad that Bill has found the creation and modification dates of OS X to be very stable as it is reassuring.

For the time being I will keep using MacJournal for logging my project because it is very nice. The research materials are all in DTP. As it happens I’ve spent the last four days working on materials in DTP in a very intense period which is going to continue for some time. To write up the log I’m keeping it’s actually rather nice to switch to a different application, it feels like a sort of a break :slight_smile:

If I want to transfer log entries from MacJournal to DTP it is very easy indeed. I think that as the project develops it is very likely that I will do this in fact.

Thanks for that followup info about how MJ handles dates. I wouldn’t want a date prepended to files during export but can understand how other people might like that feature.