What exactly are “hard links” anyway?

A better question might be “why are they useful?” – which is exactly what Sam Mestman shows Steve Martin from Ripple Training on this week's episode of MacBreak Studio.

Hard links allow the Finder to represent files on a single volume in multiple locations – not as symbolic links or aliases, but as the actual files. So they appear in multiple locations but don't take up any additional disk space. This capability has far-reaching implications for media management in Final Cut Pro X.

Sam discusses a scenario of a workgroup of editors using media on a shared storage location. To show how hard links work, he first imports about 100GB of media using the “leave in place” option: doing so creates aliases of the media in the library. So the library, also located on the same drive as the media, stays small and simply points to the original media location. The import process is very fast since no actual copies are being made. However, the library is still dependent on those external media sources: if they are deleted, they will disappear from the library.

Next, Sam copies the media into the library using Final Cut Pro's consolidate function. This process replaces all the symbolic links in the library with the actual media files. Here's where the magic of hard links occurs: even though he is “copying” 100GB of media, because both the library and the media are on the same drive, the process takes only a few seconds. After consolidating, Sam confirms that the library has grown by 100GB in size, the symbolic links have been replaced by actual media files in the library, and the original media is still in its original location outside of the library. However, the total used drive space hasn't changed at all!

To prove his point, Sam then quits Final Cut Pro X, deletes the folder of source media and empties the trash. Upon relaunching FCP X all the media is still online – and the drive space remains unchanged.

What this means is that multiple editors can each have their own consolidated libraries of copies of source media, accomplishing the task extremely quickly because no actual media is copied. Changes to the source media won't affect their media. And these libraries can be moved to other volumes, at which point real full copies of the media will be made. Check it all out in the video above.