> didn't Plan 9 have a very interesting persistence concept that did away with the entire notion of "saving" something — very similar to editing a document in a

> didn't Plan 9 have a very interesting persistence concept that did away with the entire notion of "saving" something — very similar to editing a document in a web app nowadays, except locally? Though I find that to be an absolute mismatch when I'm opening a document for reference purposes only, which means that any edits I might make are either accidental or otherwise only meant to be temporary (like if I'm opening a DWG drawing of a plan and am drawing some additional auxiliary lines to take some measurements or something like that). Automatically saving a safety copy to guard against program crashes or something like that is fine, but automatically overwriting the master file with my changes definitively isn't the right thing in that case…