The internal-tracking-system (ITS) of the ALICE detector at I,I-IC, consist
s of six concentrical barrels of silicon detectors. The outmost two layers
are made of double-sided strip detectors (SSD). In the framework of a R&D,
the characteristics and performances of these devices, manufactured by two
different companies, associated with their designed read-out electronics, h
ave been studied off- and in-beam at the SI'S (CERN). The results are prese
nted and discussed.