Information:  - In computing, the process identifier (normally referred to as the process ID or just PID) is a number used by most operating system kernels  such as that of UNIX, macOS or Microsoft Windows  to uniquely identify an active process. This number may be used as a parameter in various function calls, allowing processes to be manipulated, such as adjusting the process's priority or killing it altogether.  - A kernel panic (sometimes abbreviated as KP) is an action taken by an operating system upon detecting an internal fatal error from which it cannot safely recover. The term is largely specific to Unix and Unix-like systems; for Microsoft Windows operating systems the equivalent term is "Stop error" (resulting in a "Stop error screen," or colloquially, a "Blue Screen of Death").  - Musik filename (also written as two words, file name) is a name used to uniquely identify a computer file stored in a file system. Different file systems impose different restrictions on filename lengths and the allowed characters within filenames.  - Unix (trademarked as UNIX) is a family of multitasking, multiuser computer operating systems that derive from the original AT&T Unix, developed starting in the 1970s at the Bell Labs research center by Ken Thompson, Dennis Ritchie, and others.  - Process supervision is a form of operating system service management in which some master process remains the parent of the service processes.  - runit is an init scheme for Unix - like operating systems that initializes , supervises , and ends processes throughout the operating system . Runit is a `` reimplementation '' of the `` seminal '' daemontools process supervision toolkit that runs on the Linux , Mac OS X , * BSD , and Solaris operating systems . Runit features parallelization of the start up of system services , which can speed up the boot time of the operating system . Runit is an init daemon , so it is the direct or indirect ancestor of all other processes . It is the first process started during booting , and continues running until the system is shut down .  - In computing, booting (or booting up) is the initialization of a computerized system. The system can be a computer or a computer appliance. The booting process can be "hard", e.g., after electrical power to the CPU is switched from off to on (in order to diagnose particular hardware errors), or "soft", when those power-on self-tests (POST) can be avoided. On some systems a soft boot may optionally clear RAM to zero. Both hard and soft booting can be initiated by hardware such as a button press, or by software command. Booting is complete when the normal, operative, runtime environment is attained.  - Daniel Julius Bernstein (sometimes known simply as djb; born October 29, 1971) is a German-American mathematician, cryptologist, programmer, and professor of mathematics and computer science at the Eindhoven University of Technology and research professor at the University of Illinois at Chicago. He is the author of the computer software programs qmail, publicfile, and djbdns which he released as license-free software, later as public domain software.  - In Unix-based computer operating systems, init (short for "initialization") is the first process started during booting of the computer system. Init is a daemon process that continues running until the system is shut down. It is the direct or indirect ancestor of all other processes and automatically adopts all orphaned processes. Init is started by the kernel using a hard-coded filename; a kernel panic will occur if the kernel is unable to start it. Init is typically assigned process identifier 1.  - daemontools is the "seminal process supervision toolkit" written by Daniel J. Bernstein as an improvement to the "inittab", "/etc/ttys", "init.d" or "rc.local" alternatives, providing all of the following features.  - An operating system (OS) is system software that manages computer hardware and software resources and provides common services for computer programs. All computer programs, excluding firmware, require an operating system to function.    After reading the paragraphs above, we are interested in knowing the entity with which 'runit' exhibits the relationship of 'instance of'. Find the answer from the choices below.  Choices: - 1  - action  - bell  - booting  - computer  - computer file  - family  - file  - free software  - function  - identifier  - kernel  - killing  - may  - microsoft windows  - name  - number  - october  - operating system  - process  - research  - research center  - running  - science  - service  - software  - system software  - term  - two  - will
A:
free software