sentences:  Elements of the ES7000 architecture includes
  
  This server family has undergone several model revisions in its lifetime since 1999.Initially, the servers were standalone—physically the configuration resembled a rack and took up a somewhat larger footprint than a rack (Models 100, 130, 200, 230, 550, 400).Second and third generation ES7000s were rack mountable cells 4U or 3U high that fit in standard 19" racks.