Performance Co-Pilot (PCP) is a framework and set of services for supporting system-level performance monitoring and performance management. It provides a unifying abstraction for all of the interesting performance data in a system, and allows client applications to easily retrieve and process any subset of that data using a single API. A client-server architecture allows multiple clients to monitor the same host, and a single client to monitor multiple hosts. Archive logging and replay are integrated so that a client application can use the same API to process real-time data from a host or historical data from an archive.
If you're a developer of multiple projects, you'll find yourself needing to switch between multiple different version control systems. After working in one (e.g. SVN) for an hour, you may need to switch to a different one (e.g. git). Getting your fingers to switch is the difficult part, or remembering the right command line flags to use for the given tool. That's where The One Ring comes in: it provides a constant interface to all the version control systems, and your fingers only need to remember a single command regardless of what checkout directory your shell is sitting in.