Other implementations for parts of the framework exist.
The language has an open, published specification, and multiple implementations exist.
Other implementations of the 9P file system protocol also exists for many other systems and environments.
Chatroom-based implementations of the party game Mafia also exist.
A fourth implementation exists in the Linux kernel source code since at least version 2.6.10.
Many other implementations exist, provided with both various operating systems and C compilers.
Many implementations may exist for a given specification or standard.
However many inconsistent implementations and extensions to the basic format exist.
Open-source, in addition to proprietary, implementations exist for these.
It is currently very popular and implementations exist for all major operating systems.