In article , Wolf K
wrote:

On 2017-12-14 19:31, Your Name wrote:
Purely data files, such as a JPEG image or Word document, did not have
any resource fork at all, not even an empty one. They didn't need one
because there are no resources. That's why if you try to open a data
file in ResEdit it says there is no resource fork and asks if you want
to add one. (An optional add-on did allow ResEdit to open the data fork).

Mainly it was only applications that had resource forks.

Many people confuse the Finder's information as being part of the
resource fork, but they are different. The Finder's information is not
stored inside the file at all.

Thank you.

be aware that the first part is completely wrong, as i said yesterday.

*every* files had *both* a resource *and* data fork (either or both of
which could be empty), including what he calls 'purely data files',
otherwise known as documents.

inside mac, volume i, page 105-6:
https://i.imgur.com/88pKuDl.jpg
https://i.imgur.com/ESsqRji.jpg

documents used the data fork, resource fork or both, depending on what
worked best for that particular app. for example, text editors would
put the text in the data fork (and compatible with non-mac systems),
but might also include a custom font or scroll position in the resource
fork. preference files often used only the resource fork.

applications had code & assets in the resource fork, with the data fork
often used for personalization (name, serial#, etc.) but could also be
used for many other things or could be empty.