Hydra was designed to be modular and secure, and intended to be flexible enough for easy experimentation.[3]
The system was implemented in the programming language BLISS.[4]
Levin, R.; Cohen, E.; Corwin, W.; Pollack, F.; Wulf, William (November 1, 1975). "Policy/mechanism separation in Hydra". Proceedings of the fifth ACM symposium on operating systems principles. pp. 132–140. doi:10.1145/800213.806531. S2CID10524544.