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So to avoid these ends, let's avoid these beginnings: avoid multi-threading. Use single-threaded programs, which are easier to design, write, and debug than their shared-memory counterparts. Instead, use multiple processes to extract concurrency from the hardware. Choose a communication medium that works just as well on a single machine as it does between machines, and make sure the individual processes comprising the system are blind to the difference. This way, deployment becomes flexible and scaling becomes simpler. Because communication between processes by necessity has to be explicitly designed and specified, modularity almost happens by itself.