Hydra (stylized as HYDRA) is an early, discontinued, capability-based,

object-oriented Object-oriented programming (OOP) is a programming paradigm based on the concept of "objects", which can contain data and code. The data is in the form of fields (often known as attributes or ''properties''), and the code is in the form of ...

microkernel In computer science, a microkernel (often abbreviated as μ-kernel) is the near-minimum amount of software that can provide the mechanisms needed to implement an operating system (OS). These mechanisms include low-level address space management, ...

designed to support a wide range of possible

operating system An operating system (OS) is system software that manages computer hardware, software resources, and provides common daemon (computing), services for computer programs. Time-sharing operating systems scheduler (computing), schedule tasks for ef ...

s to run on it.Wulf 74 pp. 337–345 Hydra was created as part of the

C.mmp The C.mmp was an early ''multiple instruction, multiple data'' ( MIMD) multiprocessor system developed at Carnegie Mellon University (CMU) by William Wulf (1971). The notation ''C.mmp'' came from the PMS notation of Gordon Bell and Allen Newell ...

project at

Carnegie-Mellon University Carnegie Mellon University (CMU) is a private research university in Pittsburgh, Pennsylvania. One of its predecessors was established in 1900 by Andrew Carnegie as the Carnegie Technical Schools; it became the Carnegie Institute of Technology ...

in 1971. The name is based on the

ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic pe ...

mythological creature

the hydra ''The Hydra'' was a magazine produced by the patients of the Craiglockhart War Hospital, noteworthy for having been edited at one time by Wilfred Owen, and for including poems by Siegfried Sassoon. The magazine was headquartered in Edinburgh. A ...

. Hydra was designed to be modular and secure, and intended to be flexible enough for easy experimentation. The system was implemented in the programming language

BLISS BLISS is a system programming language developed at Carnegie Mellon University (CMU) by W. A. Wulf, D. B. Russell, and A. N. Habermann around 1970. It was perhaps the best known system language until C debuted a few years later. Since then, C b ...

References

* * {{Operating-system-stub Capability systems Carnegie Mellon University software Microkernels Microkernel-based operating systems Object-oriented operating systems