From Ars Technica’s Syncing vs. saving, and the case for a home storage cloud: “A ‘disk’ is…a storage abstraction that hides all sorts of sync activity from you, the user. So as you use a computer, the different levels of the storage hierarchy (registers, cache, main memory, hard disk) are all ’syncing’ different copies of the data on which you’re working, but your exposure to the nuts and bolts of that sync is largely limited to the ‘Save’ command in whatever application you’re using. When you ’save a file,’ what you’re really doing is syncing different storage pools, all of which are hidden from you by the abstraction that is the ‘disk drive.’ So what I’m proposing is that we hide all of the separate ‘disk drives’ in an average home behind an even larger abstraction: ‘the cloud.’”