I am trying to create a very big matrix with big.matrix from package big.memory in order to apply dbscan afterwards. I have two problems: I need to create 4 matrices with 120000 rows X 120000 columns. I have tested various R packages for big data (particularly bigmemory and ff). Since ff cannot create matrices bigger than 45000 x 45000 (aproximatly) due to value .Machine$integer.max, I tried package bigmemory. I tried to create a matrix and it indeed created file .bin with size 107GB, but failed to create the .desc file also necessary. I would like to know if this is not possible dut to the size or any other technical reason. The second problem is to use these types of matrix (as dissimilarity matrix) in dbscan, since I tried to pass them as argument but it cannot convert it do data.frame nor matrix dut to unavailability of the necessary amount of RAM (obviously). If anyone has ever dealt with one or both of these problems, please let me know how you achieved it. Thanks. Tiago Cunha -- Tiago Daniel S? Cunha Faculdade de Engenharia da Universidade do Porto Skype: tiagodscunha Facebook: http://www.facebook.com/TiagoDSCunha Email alternativo 1: ei08142 at fe.up.pt Email alternativo 2: tiagodscunha at hotmail.com