delgon developed a miner that cleaned up the original ghostrider miner that was developed by tri and also provided 32 and 64 bit arm support. this came out before the wyvern miner.
Some claim delgon wrote cpuminer from the ground up. It's all bull shit.
Ghostrider is a mix of X16R and Cryptonight built on top of Pooler's original cpuminer, expanded by TPruvot, with Wolf's Cryptonight
optimisations and my X16R optimisations.