data flow

A data flow architecture or language performs a computation

when all the operands are available. Data flow is one kind

of data driven architecture, the other is demand driven.

It is a technique for specifying parallel computation at a

fine-grain level, usually in the form of two-dimensional

graphs in which instructions that are available for concurrent

execution are written alongside each other while those that

must be executed in sequence are written one under the other.

Data dependencies between instructions are indicated by

directed arcs. Instructions do not reference memory since the

data dependence arcs allow data to be transmitted directly

from the producing instruction to the consuming one.

Data flow schemes differ chiefly in the way that they handle

re-entrant code. Static schemes disallow it, dynamic

schemes use either "code copying" or "tagging" at every point

of reentry.

An example of a data flow architecture is MIT's VAL

machine.