Hi B747Pilot,
I have tried Mac XView with XP11 and I believe that the code is working. Both XP11 (including XView) and PSX run satisfactorily separately. However, on my low-end Mac they don't run together.
My Mac is a Mini and was bought solely for building the OSX version of the software. It has an i7 processor with just 2 cores. When I run both simulators, XP11 takes over most of the CPU and PSX is only able to achieve a frame rate of around 4fps with the CPU resources remaining. This gives an erratic behaviour like you describe and it is impossible to fly.
Check the frame rate that you are achieving with PSX in the top left corner of the screen to see if this is your problem. If it is, then there are a number of options. You can run PSX on a separate machine, using the most powerful machine for XP as PSX doesn't use so many resources. I can help you with the network settings for that if necessary. The second machine could be a PC.
Alternatively you can download a demo copy of XP10 and try that. With this both sims run satisfactorily on my Mac.
XP11 has been developed to maximise performance by using all the available cores, whereas the older versions typically used one or two cores. This has not been a problem with Windows, as the user can set the processor affinity to limit the number of cores a particular application has access to. As I understand it, this is not possible with OSX - somebody please correct me if I am wrong.
Please let me know how you get on.
Mike