Portable Operating System Interface (POSIX)
Definition - What does Portable Operating System Interface (POSIX) mean?
The Portable Operating System Interface (POSIX) is a set of interface standards specified by the IEEE computer society and based on UNIX. It provides the definition for the application programming interfaces, the associated utility interfaces and command line shells for compatibility of different applications and software with different operating systems and variants of UNIX. POSIX is an evolving family of computer standards that consists of a wide spectrum of operating system components ranging from the C programming language and interfaces based on shell to administration of computer systems.
Techopedia explains Portable Operating System Interface (POSIX)
The Portable Operating System Interface evolved from the requirement of different organizations to have applications and programs that could be moved to different computer systems without the need for recoding. The UNIX operating system was selected as the standard system interface as it was capable of being “manufacturer neutral.” Although there have been many releases for portable operating system interface, POSIX 1 which defines system calls and POSIX 2 which defines command line interfaces are important ones.
The Portable Operating System Interface is recognized by standards such as the International Organization for Standardization (ISO) and American National Standards Institute (ANSI). One of the biggest roles of POSIX is to ensure code portability and compatibility between the different systems and hardware platforms. This is increasingly checked for many government agreements and commercial applications. Modern commercial implementations based on UNIX and even free ones based on UNIX are mostly POSIX compliant.