POSIX

POSIX

POSIX (acronym for Portable Operating Ssystem Interface, and X stands for UNIX as a hallmark of the API) is a standard written by the IEEE, which defines a standard operating system interface and environment, including a command interpreter (or &# 34;shell").

The term was suggested by Richard Stallman in the 1980s, in response to a demand from the IEEE for a name that was easy to remember. The translation of the acronym is "Portable Operating System Interface".

Introduction

POSIX is a written standard and a registered trademark of the Institute of Electrical and Electronics Engineers. This standard defines a standard operating system interface and environment, including a command interpreter (or "shell"), and common utility programs to support application portability at the source code level. The name POSIX arose from the recommendation of Richard Stallman, who was then on the IEEE committee in the 1980s.

A series of tests accompany the POSIX standard. They are called "PCTS" referring to the acronym "Posix Conformance Test Suite". Since the IEEE began charging high prices for POSIX documentation and has refused to publish the standards, the use of the Single Unix Specification model has been increased. This model is open, accepts input from all over the world, and is freely available on the Internet. It was created by The Open Group.

Parts

• POSIX.1, Core Services (implements standard ANSI C calls). Includes:
  • Process creation and control.
  • Signals.
  • Floating point perceptions.
  • Segment rape exceptions.
  • Exceptions for illegal instruction.
  • Bus mistakes.
  • Timer.
  • File and directory operations (on any mounted fs).
  • TuberiasPipes).
  • Standard Library of C.
  • Input/output and device control instructions (ioctl).

• POSIX.1b, real-time extensions:
  • Planning (scheduling) with priority.
  • Real-time signals.
  • Timer.
  • Semaphores.
  • Step of messages (message passing).
  • Shared memory.
  • Entrance/exit synchronous and asynchronous.
  • Memory locks.

• POSIX.1c, thread extensions (threads(c):
  • Creation, control and cleaning of threads.
  • Planning (scheduling).
  • Sync.
  • Signal handling.

• POSIX.2, Shell and Utility (IEEE Std 1003.2-1992)
  • Command interpreter
  • Utility programmes

After 1997 the Austin Group made modifications to POSIX. The specifications are called the Single Unix Specification.

• POSIX:2001 or IEEE Std 1003.1-2001 is equivalent to version 3 of Single UNIX Specification.
  • The basis of definitions, Item 6.
  • System interfaces and headings, Item 6.
  • Commands and utilities, Item 6.

• POSIX:2004 or IEEE Std 1003.1-2004 implies a small update of POSIX:2001. He's got two technical bug fixes.

• Since 2009 POSIX:2008 or IEEE Std 1003.1-2008 represents the current version.
  • The basis of definitions, Item 7,
  • System Heading Interfaces, Item 7.
  • Commands and utilities, Item 7.

Compatibility

Fully POSIX Compliant

The following Operating Systems are 100% compatible with one or more POSIX standards:

Mostly POSIX Compliant

The following, while not officially certified as POSIX compliant, largely conform:

POSIX for Windows

• Cygwin offers largely POSIX-compatible development and an execution environment for Microsoft Windows.
• Microsoft POSIX subsystem, an optional Windows subsystem.
• Windows Services for UNIX Microsoft allows full POSIX compatibility for certain Microsoft Windows products. Windows NT-based operating systems up to Windows 2000 had a built-in POSIX interface on the operating system and UNIX Services for Windows provided a UNIX-type environment. For Windows XP, UNIX Services for Windows should be installed for POSIX compatibility. The UNIX subsystem is incorporated into the Enterprise and Ultimate editions of Windows Vista and 7, and cannot be added separately to the other editions..
• UWIN AT fakeT Research implements a POSIX layer on Win32 application program interface (API)
• MKS Toolkit