VxWorks is a proprietary real-time operating system designed by Wind River.
VxWorks is POSIX compliant for user-mode applications.
VxWorks supports 32-bit and 64-bit architectures, including architectures from Intel, ARM and PowerPC.
VxWorks is used frequently in the aerospace and space sector. For example, NASA used VxWorks to run on the Mars Rover.
The Wind River Workbench comes with a simulator that is able to run VxWorks code.