Dates shown in Dolphin

[DoYouKubuntu]

I'm confused by the dates shown in Dolphin. There are several available, but two of them seem to be reversed.

The three in date choices are:

- Modified
- Created
- Accessed

In the "Image" menu, there's also:

- Date photographed

Modified and created seem to be reversed. Here's an example: an image photographed on 12/22/15 shows its modified date as 11/16/20, its created date as 03/02/22, and its accessed date as 06/21/22 (today). Do you notice how the created date is two years AFTER it was modified?! How can a file be modified if it hasn't been created yet?

Can anyone explain this weirdness to me? Or do we just accept it for what it is? FWIW, I happen to recognize the modified date as the date the file was copied to my former laptop. I have no idea what happened to it on its 'created' date of 03/02/22--my memory's not that good! But its *real* creation date is 12/22/15, i.e., the date it was photographed (and dumped to my then-current computer).

[claydoh]

So, the last time the file was changed was when it was on the other computer (2020), and the creation date was the date then was file created on ---or more precisely, written to -- the new drive (2022).
Images also have extra info embedded in the file itself -- the exif data, such as the date it weas taken, camera and lens info, etc. These are shown by most image utilities, and dolphin can be configured to show this as well.

This exif data is unrelated to the physical file dates you are looking at.

Preserving the 'surface' dates (if desired) would involve cloning/syncing/zipping, which usually have options to preserve this.

[DoYouKubuntu]

So, the last time the file was changed was when it was on the other computer (2020), and the creation date was the date then was file created on ---or more precisely, written to -- the new drive (2022).

No, the last time it was changed was 03/02/22, which is shown as its creation date. The file was copied (from an external drive) to the new computer on 11/16/20, which is shown as its modified date. I think those are reversed.

The accessed date is correct, as is the date photographed.

Images also have extra info embedded in the file itself -- the exif data, such as the date it weas taken, camera and lens info, etc. These are shown by most image utilities, and dolphin can be configured to show this as well.

Right.

This exif data is unrelated to the physical file dates you are looking at.

Right.

Preserving the 'surface' dates (if desired) would involve cloning/syncing/zipping, which usually have options to preserve this.

I'm not sure what you mean by 'surface' dates. All I want is to see the actual *creation* date and *modified* date--which seems pretty simple to me. I create a new file, its creation and modified dates are right now. Tomorrow, I edit that file, its creation date stays the same and its modified date becomes whatever right now is tomorrow. But that's not what I'm seeing. What am I missing?

[claydoh]

I dunno, your systems seem to do weird stuff

For my photos I ignore the physical file dates, and just search for things via the exif data that the camera stored in the actual image, and not the general file attributes.

[jlittle]

You, and photo copying software, can easily set whatever modification and access timestamps that seem useful (and the filesystem supports).

Note that for decades, Unix and Linux did not have a proper file creation date (and some older file systems don't). As a workaround, the time of last change to the inode was used as a creation date, because as a file is accessed or written to it didn't change. But, chown and chmod would change it. Linus Torvalds resisted having a "birth date" in Linux for a long time, because IIUC it meant some system calls had to change, but it happened about 5 years ago. A lot of software still doesn't know about birth timestamps.

It's hard to change the birth date of a file in Linux (it can be done, see unshare). So it's common for photo copying software to set the modification timestamp of files to the timestamp the photo was taken, but the birth timestamp gets left as that of the file's creation on the local file system.

(Curious about file system support, I tried setting old modification timestamps on files. btrfs let me set any year back to 0 , but ext4 clamped the date to be on or after 1901-12-14.)