Chapter 1 The Potential for Parallel Computation Humans generally think in a sequential manner. Computers don't think, if they did they would probably wonder why parallel processing is not used by humans.
Parallel processing involves topic like algorithms, hardware and languages.
Sequential programing is easy to write and understand by humans, but obviously, it can be very slow. Parallel deals with this problem and looks for ways to speed up the programs. Threads and dataflow were an attempt to increase processing speed. Multiple sequential instruction streams calls for multiprocessors or you don't gain speed. Dataflow drops the idea of flow and every instruction has its dependencies listed so you still have instructions that need to be completed before one another but no set time when these are to be done.