These versions of DDLAB where complied for Mac OSX, 32-bit or 64-bit. 32-bit DDLab runs on a 64-bit system, but not vice versa. Run from a terminal in X11, which must be installed. ddlabm08 behaves mostly as described in Exploring Descrete Dynamics ddlabm08_mac32 ..32-bit compiled in Mac OSX 10.4.11 ddlabm08_mac64 ..64-bit under construction ddlabx09 allows bigger networks ddlabx09_linux32 ..32-bit compiled in Mac OSX 10.4.11 ddlabx09_linux64 ..64-bit under construction to run DDLab, from a terminal in X11: from the directory with the DDLab files, enter the name of the executable preceded by ./ and followed by & for example ./ddlabm08_mac32 & or ./ddlabx09_mac32 & alternatively, first change directory to "ddfiles" then enter the name of the executable preceded by ../ and followed by & This will keep files generated by DDLab in the ddfiles subdirectory. ---------------------------------------------------