The soft-instruction software architecture has been described. This architecture supports implementation of general purpose concurrent system software. Soft-instructions provide many of the benefits of the synchronous/reactive languages that assume the strong synchrony hypothesis, while providing program source that is easier to read, comprehend, and maintain. In addition, the soft-instruction architecture can coexist with existing systems, can flexibly adapt to many environments, and has many similarities to the hardware instruction set architectures with which systems programmers are very familiar.