The mining hardware does a double sha-256 hash of the header while mining. Is each sha-256 operation counted when determining the hash rate or is the whole sha256(sha256(header)) counted as one hash?
Just to throw out some example numbers, if the hardware can do 300 Mhash/s is the hash rate 300 Mhash/s or is it 150 Mhash/s because two sha-256 operations are required for each attempt?