Can a multi-threaded program ever be deterministic?

Question

Normally it is said that multi threaded programs are non-deterministic, meaning that if it crashes it will be next to impossible to recreate the error that caused the condit

Answer 1

It would be possible to run a program on a virtual multi-threaded machine where the allocation of virtual cycles to each thread was done via some entirely deterministic process, possibly using a pseudo-random generator (which could be seeded with a constant before each program run). Another, possibly more interesting, possibility would be to have a virtual machine which would alternate between running threads in 'splatter' mode (where almost any variable they touch would have its value become 'unknown' to other threads) and 'cleanup' mode (where results of operations with known operands would be visible and known to other threads). I would expect the situation would probably be somewhat analogous to hardware simulation: if the output of every gate is regarded as "unknown" between its minimum and maximum propagation times, but the simulation works anyway, that's a good indication the design is robust, but there are many useful designs which could not be constructed to work in such simulations (the states would be essentially guaranteed to evolve into a valid combination, though one could not guarantee which one). Still, it might be an interesting avenue of exploration, since large parts of many programs could be written to work correctly even in a 'splatter mode' VM.