A magnetic head assembly includes a read head with a current perpendicular to the planes sensor. The composting material is contained in a trough, and is turned by means of an apron, which is supported in a carriage for a travelling along the trough. Responsive to executing the second code in the second node, the second node establishes a communication channel with a third node, replicates itself to generate third code, and provides the third code to the third node over the communication channel. Each output sample may be a linear combination of at least two input samples.