On Fri, Jul 11, 2025 at 13:39:44 +0100, mick.crane wrote: > When moving files on the same disk impression is, at least with dragging in > the desktop file manager, it seems instant. Whereas to another disk seems to > make new files. I guess that when on the same disk the OS changes only > something about the file description?
Essentially, yes, this is correct. The key here is whether the file is moving to a different file system, or to a different directory within the same file system. If the file is moving within the same file system, then the *data* don't have to be copied. Only the directory listings that point to the data have to be updated. If the file is moving to a different file system, then the data have to be copied over, in addition to updating the directory listings on both file systems, and then finally marking the storage space as available for use on the original file system. Even if the two file systems are on the same physical disk, a move of a file from one file system to the other will still entail a full copy.
