Shardus is building distributed ledger software to remedy the problems of traditional blockchains -- scalability, decentralization and efficiency. The technology being developed will use compute and state sharding to accommodate billions of daily active users, allowing for global-scale decentralized networks.
Tera is a decentralized application platform. This is akin to an operating system. Tera consists of a repository of programs and data storage integrated into the Internet. The mechanism for publishing programs and data on this platform is free from censorship. The circulatory system is the blockchain.