The principle behind T.OS is the establishment of a commercial payment system that utilizes digital currency. This will be the first such system in the history of the world. The solution comprises two coins. The TOS coin, or TOSC, is a regular cryptocurrency coin, which is not used for commerce, but can be exchanged on regular exchanges to any other digital currency. Its value may appreciate or depreciate and that is why it can't be used for commerce.
Novacoin is a hybrid Proof of work (POW) / Proof of stake (POS) decentralized peer-to-peer cryptocurrency.The Proof of Work part of Novacoin is based on the Scrypt hashing algorithm. Proof of Stake contributes to the coins energy efficiency, as there is no need for nodes to contribute mining power to part of the money creation process. As of now, Novacoin is set to be capped at 2 billion coins. However Novacoin stated that the cap limit may be lifted if the situation requires it. It looks very much like a variation of Sunny King Peercoin.