Git does both. When you create a commit, it stores a full (zipped) copy of the object, without any deltas. Periodically (I believe it used to be every thousand

Git does both. When you create a commit, it stores a full (zipped) copy of the object, without any deltas. Periodically (I believe it used to be every thousand commits, though I'm not sure what the heuristic is today), git will take the loose objects and compress them into a pack. The full blob format is how objects are manipulated by git internally: to do anything useful, the objects need to be extracted from the blob, with all deltas applied, before anything can be done with them. It's also worth nothing that accessing a deltified object is slow (O(n) in the number of deltas), so the length of the delta chain is limited. Because deltification is really just a compression format, it doesn't matter how or where the deltas are done -- the trivial "no deltas" option will work just fine if you want to implement that. You can trivially verify this by creating commits and looking in '.git/objects/*' for loose objects, running 'git repack', and then looking in '.git/objects/pack' for the deltified packs.