Short access time and compact realisation of data storage and display devices no longer belong tobl a. oddities and will soon have many applications.This paper deals with PHEDRE and SEMIRAMIS, two solutions given to the problems of information storage.We first describe the data storage mean:Data (typically prints or pictures) is modulated by a reference beam and recorded by superimposition on small areas of photographic films or plates;Secondly, recording and retrieval procedures will be detailed.