OpenMSR uses one API for hardware access. This API is called PhysMach as abbreviation for PhysicalMachine. PhysMach exports the hardware as a set of variables and some functions to use them, that's it. The ICA application must not have any knowledge how to drive the different hardware, you can even have a micture of different hardware, and any ICA application can use it by using PhysMach.
The different ICA applications can talk to each other by using those variables.

The following list of hardware is currently supported by PhysMach:

• ISA based 8255 PIO Adapter
• DIL Net/PC
• BMCM USB-PIO and USB-AD
• IO-Warrior 40
• printer port
• joystick port
• Kolter Electronics PCI1616, OptoRel and OptoPCI