Final answer:
Linux is the experimental operating system that introduced a many-to-many relationship between threads and processes, offering high configurability and versatility which led to its widespread adoption.
Step-by-step explanation:
The experimental operating system that explored the idea of having a many-to-many relationship between threads and processes was Linux.
This concept is part of the operating system's ability to allow for each process to have multiple threads and vice versa, enhancing multitasking and system resource utilization. Linux was created by Linus Torvalds in 1991 as a free alternative to the more expensive UNIX systems.
With its open-source nature, Linux gained rapid popularity for its configurability and versatility, leading to a diverse range of OS distributions such as Red Hat, Debian, Ubuntu, Darwin, and Android. It became a valuable resource for running servers, internet routers, and even rivaled proprietary supercomputers with clusters of networked Linux-powered PCs.
Linux is the experimental operating system that introduced a many-to-many relationship between threads and processes, offering high configurability and versatility which led to its widespread adoption.