FATMEN removes the necessity of having to know details such as which tape or disk a file is on. In addition, commands or subroutine calls to access data are identical on all supported systems (currently VM/CMS, MVS, VAX/VMS and Unix). Thus, one can take the same code from machine to machine and access data in a transparent manner, although the underlying mechanism or even the copy of the data may be completely different.
In addition, through the FATMEN catalogue, users may list characteristic of a data set, such as a comment field, user words, file format etc. which otherwise would have to be recorded in a log book or NEWS item.