Thanks for this. Question for the developers: what do I need to hash, exactly to get the sha-256 hash for this block? Is it the JSON, or is it kept in some other data format in the database? I’m interested in generating blocks myself, and am not clear what exactly is being hashed.
More detail on the block hashing algorithm can be found here: http://www.bitcoin.org/wiki/doku.php?id=block_hashing_algorithm
(or look at the code.)