These pages describe the flow of data through the different programs. File names, formats and contents is listed. 2dx and the underlying MRC programs process and then evaluate images, and extract values for amplitudes and phases of Fourier spots. These are then handed over from one program to the next one, where each program does something to those values (e.g. correcting for the CTF, or merging several values together). Each program thereby unfortunately needs a different type of data that is therefore often in a different format, and the whole thing quickly gets very confusing. Most of these files are text files (ASCII), though, so that you can always open them with a text browser (vi, edit, SimpleText, or even Word (but don't save it back as "Word" file.doc file). We have here compiled a list of all the programs that are called in sequential order, and have listed the input and output files for these programs. For the output files we have then included a short description of the file format, followed by an example of how that should look like. This is only for reference purposes, in case somebody tries to follow the flow of data from one program to the next one.