There are few experimental data flow computer projects. The associates at MIT have developed a tagged token architecture for constructing data flow computers.
The global architecture incorporates n processing elements (PEs) inter-connected by an n x n routing network. The complete system provides pipelined data flow operations in all n PEs. Inter PE communications are completed by the pipelined routing network.
In each PE, the machine offers a low-level token matching structure that sends off only those instructions whose input data are already accessible. Each datum is identified with the address of the instruction to which it belongs and the context in which the instruction is being implemented.
Instructions are stored in program memory. Tagged tokens enter the PE through a local path. The tokens can also be passed to the other PE through the routing network. All internal circulation operations are pipelined without blocking.
It can conceive instruction address in a dataflow computer as replace the program counter & the context identifier replacing the frame base register in control flow computer. It is the machine’s job to match up data with the same tag to needy instructions. In so doing, new data will be produced with a new tag indicating the successor instructions.
Thus each instruction represents a synchronization operation. New tokens are formed and circulated along the PE pipeline for sense or to other PEs through the global path, which is also pipelined.