POSIXModell

POSIXModell is a standardized interface for operating systems, defined by the IEEE and The Open Group. It specifies a set of APIs for software compatibility with variants of Unix and other operating systems. The term "POSIX" stands for Portable Operating System Interface. The POSIXModell aims to ensure that software written for one POSIX-compliant system can be easily ported to another, promoting interoperability and reducing the need for system-specific code.

The POSIXModell covers various aspects of an operating system, including file I/O, process control, inter-process communication, and more. It defines a consistent interface for these functionalities, allowing developers to write code that can run on different systems without modification. This standardization is particularly important in the context of Unix-like operating systems, which have a long history of diversity and fragmentation.

The POSIXModell has evolved over time, with different versions released to incorporate new features and address emerging needs. The most widely used versions are POSIX.1 (also known as IEEE 1003.1), which covers the core interface, and POSIX.1b (IEEE 1003.1b), which adds real-time extensions. Other extensions, such as POSIX.1c (threads) and POSIX.1d (real-time), have also been developed to address specific requirements.

Adherence to the POSIXModell is not mandatory, but it is widely adopted in the industry due to its benefits in terms of portability and compatibility. Many modern operating systems, including Linux and various Unix variants, are POSIX-compliant, making it a valuable standard for developers.