The first time I edited any media, I did it with a razor and some sticky tape. It wasn’t a complicated edit – I was stitching together audio recordings of two movements of a Mozart piano concerto. It also wasn’t that long ago and I confess that every subsequent occasion I used a DAW (Digital Audio Workstation). I’m guessing that there aren’t many (or possibly any) readers of this blog that remember splicing video tape together (that died off with helical-scan) but there are probably a fair few who have, in the past, performed a linear edit with two or more tape machines and a switcher. Today, however, most media operations (even down to media consumption) are non-linear; this presents some interesting challenges when storing, and possibly more importantly, recalling media. To understand why this is so challenging, we first need to think about the elements of the media itself and then the way in which these elements are accessed.