On 9/4/07, David Tweed <david.tweed@xxxxxxxxx> wrote: > On 9/4/07, Jon Smirl <jonsmirl@xxxxxxxxx> wrote: > > Git has picked up the hierarchical storage scheme since it was built > > on a hierarchical file system. > > FWIW my memory is that initial git used path-to-blob lists (as you're > describing but without delta-ing) and tree nodes were added after a > couple of weeks, the motivation _at the time_ being they were a > natural way to dramatically reduce the size of repos. > > One of the nice things about tree nodes is that for doing a diff > between versions you can, to overwhelming probability, decide > equality/inequality of two arbitrarily deep and complicated subtrees > by comparing 40 characters, regardless of how remote and convoluted > their common ancestry. With delta chains don't you end up having to > trace back to a common "entry" in the history? (Of course, I don't > know how packs affect this - presumably there's some delta chasing to > get to the bare objects as well.) While it is a 40 character compare, how many disk accesses were needed to get those two SHAs into memory? > > -- > cheers, dave tweed__________________________ > david.tweed@xxxxxxxxx > Rm 124, School of Systems Engineering, University of Reading. > "we had no idea that when we added templates we were adding a Turing- > complete compile-time language." -- C++ standardisation committee > -- Jon Smirl jonsmirl@xxxxxxxxx - To unsubscribe from this list: send the line "unsubscribe git" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
