In certain situations, a user may want to save (dump) a full Warp simulation or save data associated with a Warp simulation in an external file, or to retrieve data stored in an external file (from either a Warp simulation or other source) for use in Warp. These two cases are outlined in the links below. In the case of a full dump of a run, the simulation can be continued from the time it was saved or the state of the simulation at the instant of the save can be further analyzed in full detail. The other case of saving simulation data to an external file often occurs when summarizing limited properties of a series of simulations. For example, an overlay plot comparing rms emittance evolution histories of different Warp simulations might be generated by first saving the emittance history data of the runs to external files and then reading saved data into an external graphics program or back into Warp to use the graphics capabilities of Warp in a separate Warp "simulation" carried out to generate the comparison plot. Another situation involving retrieval of data in external files that often occurs is when data files employed to describe a component of a simulation (ex: gridded magnetic field components of a focusing optic or electromagnetic field components in an rf cavity) are read into Warp to setup the simulation.