POSIXn

POSIX, short for Portable Operating System Interface, is a family of standards specified by the IEEE Computer Society for maintaining compatibility between operating systems. The standards are maintained by the Austin Group, a collaboration of technical experts from various organizations. POSIX defines the application programming interface (API), command line shells, and utility interfaces for software compatibility with variants of Unix and Unix-like operating systems.

The POSIX standards are organized into several parts, each covering different aspects of system behavior. The most well-known parts include:

- POSIX.1: Defines the core API, including system calls, input/output operations, process control, and signal handling.

- POSIX.2: Specifies the shell and utilities, including commands and utilities for file manipulation, text processing, and system administration.

- POSIX.3: Focuses on real-time extensions, providing mechanisms for real-time computing, including real-time signals, timers, and scheduling.

- POSIX.4: Covers real-time interprocess communication, defining mechanisms for communication between processes in real-time systems.

- POSIX.1003.1: Also known as POSIX.1, this part is the base standard for the C language interface to the operating system.

POSIX standards are widely adopted in various operating systems, including Linux, macOS, and BSD variants. They provide a consistent interface for developers, ensuring that applications written for one POSIX-compliant system can often be ported to another with minimal changes. This interoperability is crucial for the development of portable and reliable software.

The POSIX standards have evolved over time to incorporate new technologies and address emerging needs in computing. The ongoing development and maintenance of these standards ensure that they remain relevant and effective in the ever-changing landscape of operating systems and software development.