Beginning with the master process, the file is opened and header information written to the file. The master process writes its data then signals process with an MPI call to write its own data. Once this process has written its data, it signals the next process and the cycle continues until all processes have written their data. In addition to signalling the next process to write data, the renumbered node offset (a long integer) is also sent between processes. This value is necessary for the correct numbering of nodes in the output file. Each worker process must wait, idle, for the signal to write data and once finished must return to idle until all processes have completed their individual writes.