You don't have problems with that in BM. BM does simply not feature multi core so the potential problems simply can not arise.
Rubbish. While yes, BlitzMAX is a single threaded process, and thus not prone to concurrency problems, unless BlitzMAX specificly sets a the processor affinity to only run on a single processor/core, the process schedulers load balancing algorithm may chose to execute your program on another core/CPU in it's next time slice, depending on how much load the other core is under. Since the graphics drivers are busywaiting (that is 100% load) it's highly likely that your process is executed on seperate cores in each time slice. Hmm, interesting info, but still no closer to a solution for Flip 1 :-(
Use Linux?