VxSim, the VxWorks simulator, is a port of VxWorks to the various host architectures. It provides a simulated target for use as a prototyping and test-bed environment. In most regards, its capabilities are identical to a true VxWorks system running on target hardware. Users link in applications and rebuild the VxWorks image exactly as they do in any VxWorks cross-development environment using a standard BSP.

The difference between VxSim and the VxWorks target environment is that in VxSim the image is executed on the host machine itself as a host process. There is no emulation of instructions, because the code is for the host's own architecture. A communication mechanism is provided to allow VxSim to obtain an Internet IP address and communicate with the Tornado tools on the host (or with other nodes on the network) using the VxWorks networking tools.

Because target hardware interaction is not possible, device driver development may not be suitable for simulation. However, the VxWorks scheduler is implemented in the host process, maintaining true tasking interaction with respect to priorities and preemption. This means that any application that is written in a portable style and with minimal hardware interaction should be portable between VxSim and VxWorks.

The basic functionality of VxSim is included with the Tornado tools and is preconfigured to allow immediate access to the simulated target. The optional component of VxSim provides the simulator with networking capability.

The key differences between VxSim and other BSPs are summarized below. For a detailed discussion of subtle implementation differences which may affect application development, see H.4 Architecture Considerations.