After some testing of light-weight desktop environments I decided, at last, for installing Xubuntu (Xfce flavored Ubuntu) on my good old EEEPC 900. Xubuntu choice came because Xfce desktop environment behaved well, during my tests, working smoothly on the resource-poor EEEPC while being still able to render a modern enough user interface. Last but not least I've been using for years Xubuntu on my old desktop Sempron 2400 without problems.
Before starting with installation procedure I had to do some preliminary operation. First has been, of course, backing-up my home folder into an external USB disk (hosting all my backup since I removed original Xandros installation). Then I executed Ubuntu's disk analysis tool in order to have a hint about how to partition the new installation disks. Until now, in fact, I kept the EEEPC900 4GB on-board disk for a minimal Windows XP installation (when I bought it the EEEPC was my fastest computer) but time has come to get rid of it. So a fair distribution of disk usage among the two netbook disks is going to be important.
The disk analysis showed how my disk usage was almost evenly split between the “home” and the “usr” folder (where most of application are installed) while the rest of system folder are well less of the 4GB limit.