In 1992, Alwyn invented a simple ASCII map file format which he called EZD ("easy density"); this type of file is produced by VOIDOO and MAMA, for example, and recognised by MAPMAN (format type EZD). Later, he wanted to read such files into O directly (i.e., you would be able to look at maps directly, by-passing the MAPPAGE stage), but implementing this (the ezd_* options in O) he also changed to format (using keyworded input, for instance). In O (and the O manual), this new format is called EZD format. However, some programs are still using the old EZD format. Therefore, if you want to use EZD files in O, you should use the NEWEZD format type in MAPMAN or VOIDOO.