Clustered Object Encoding 2.0
Without going into detail about of "the cloud" and the exaggerations and mysticism that accompany it, here's some definitions that it took me a while to truly understand:
Object storage: Some manky, idiosyncratic api that allows developers to store "stuff". Avoids dealing with things like partial writes, seeks, memory maps, etc. Generally space wasteful by design. Not a place you'd want to put anything you care about. Yet, secretly, is probably the location of everythingyou care about. Your bank probably keeps your PDF statements in something like this.
Block storage: Like a horse, one can mount this kind of storage... but only for exclusive access. No shared, lockable access, no parallel reads. Essentially it's the virtual hard drive for your virtual machine from which you derive your virtual paycheck.
Clustered storage: Typically one of the above, but your data is now copied ad nauseum. Someone probably didn't stripe it. The things you expect from clustered storage, like striped files, full POSIX support, parallel writes, and erasure coding don't work in your version of the software, but every whitepaper you read refers to them.
POSIX, Erasure Coded, Clustered, Storage (PECCS): 1. This is what you actually want if you run your own data center. Used in a sentence: "Wow, that guy's got PECCS". 2. A mythical beast. 3. Maybe some company named "NextEMCApp" does it. Maybe some guy names Xavier in Spain got it to work once, but then he got hired by [SOME BIG COMPANY] and nobody heard from him again.