What is "scoreboarding"

Scoreboarding is a centralized method, used in the CDC 6600 computer, for dynamically scheduling a pipeline so that the instructions can execute out of order when there are no conflicts and the hardware is available. In a scoreboard, the data dependencies of every instruction are logged. Instructions are released only when the scoreboard determines that there are no conflicts with previously issued and incomplete instructions. If an instruction is stalled because it is unsafe to continue, the scoreboard monitors the flow of executing instructions until all dependencies have been resolved before the stalled instruction is issued.