The exchange of (binary) data between machines of different architecture is often a painful process. For NEMO binary structured files, we have devised a general portable way to port files between machines, even if both have different low level file formats (e.g. SUN OS and the Cray UNICOS OS). A different solution has been used by the MIRIAD package, which writes it's data always in the same (IEEE) format. This means a different layer of translation routines is needed for certain architectures, notably VMS and Unicos. A similar mechanism is expected to be used in NEMO in some future release.
In case the other machine has a totally different file format, it's handy to have the data in simple ASCII table format. NEMO also allows import and export of N-body data through an ASCII format described in atos It can be used directly for multiple-snapshot data, but example shell script are available to transport data.
In the case of N-body data there is no standard format to store the particle information, and we are subject to someone's favorite format. We will encounter a few, and show examples how to convert them under NEMO. In the case of images, there happens to be an astronomical standard: FITS5.16, we will discuss a few applications here too. Tables can also be transferred in an extended form of the FITS format5.17, although here the ASCII format may do equally well. Even N-body snapshots can be written in FITS format, for an example see the toy program snapfits which uses the now deprecated FITS Random Group Format.