tape
I haven't dug into the numbers myself as that is not my thing but in my talks with David Scott last month he attributed the decline almost entirely on tape. He said 3PAR had something like 90% year over year growth in Q1 anyway (and Q1 2013 was post 7000-series launch) and significant market share gains. I don't remember all the specifics but tape may of well played a big factor revenue wise. I think IBM sells tape too?
Though HP recently wrote that tape capacity shipments reached an all time record high in 2013 of 6,472 petabytes(I believe that is industry wide not just HP).
http://h30507.www3.hp.com/t5/Around-the-Storage-Block-Blog/Where-is-tape-media-headed/ba-p/167540#.U9vOJvEpKIA
Of course that is largely on the back of really big tape sizes, so fewer drives, fewer tapes but bigger sizes..