The ”cache data set” (see figure 2.8) is a very interesting functionality. As you know, Orfeo ToolBox implements processing on demand, so when you build a processing pipeline, no processing takes place unless you ask for it explicitly. That means that you can plug together the opening of a data set, an orthorectification and a spleckle filter, for example, but nothing will really be computed until you trigger the pipeline execution. This is very convenient, since you can quickly build a processing pipeline and let it execute afterwards while you have a coffee. In Monteverdi, the process is executed by saving the result of the last module of a pipeline. However, sometimes, you may want to execute a part of the pipeline without having to set the file name to the obtained result. You can do this by caching a data set. That is, the result will be stored in a temporary file which will be created in the ”Caching” directory created by the application. Another situation in which you may need to cache a data set is when you need that the input of a module exists when you set its parameters. This is nor a real requirement, since Monteverdi will generate the needed data by streaming it, but this can be inefficient. This for instance about visualization of the result of a complex processing. Using streaming for browsing through the result image means processing the visible part every time you move inside the image. Caching the data before visualization will generate the whole data set in advance allowing for a more swift display. All modules allow you to cache their input data sets.