Q&A: Folder timestamps and journalling

Q Do folders have timestamps to keep track of the last modification and original time of creation? Are these updated when metadata are modified, and how does journalling fit in with this?

A You can view the original date of creation and that of last modification to a folder either using the Finder’s Get Info dialog, or in Terminal’s command line.

Finder's Get Info dialog will show you the date of creation and modification of a folder.
Finder’s Get Info dialog will show you the date of creation and modification of a folder.

The former dialog shows the time of last modification in the ‘Modified:’ field, and that of first creation in the ‘Created:’ field. If you want a listing that you can copy and paste into a document, open Terminal, cd to the folder above the one that you are interested in, and type
ls -la

You will then see a full listing, including all folders which are distinguished by the character d at the start of the line entry, and the date and time of last modification.

Metadata that are stored within a folder will increment the time of last modification, but those used by Spotlight are kept in central index files, and there is thus no obvious indicator as to when a folder was last indexed.

Journalling is only indirectly related to any of these: it is a mechanism for storing and potentially replaying modifications made to disk volumes, to make them more robust.

Each disk write action performed is logged in that volume’s journal, and marked when that change has been committed to disk. If your Mac crashes before some actions have been completed, when you restart it those actions listed in the journal that have not been completed will be replayed, so as to bring the volume back into sync. This greatly reduces the risk of errors occurring, which could gradually grow until the volume has significant damage. It is thus a valuable measure for preserving disk health.

Updated from the original, which was first published in MacUser volume 28 issue 14, 2012.