Worldwide external disk storage systems factory revenues posted 9.8% YTY growth in Q4 2007 and totaling $5.3 bln, according to the IDC. For the quarter, the total disk storage systems market grew to $7.5 bln, up 7.6% from the prior year’s Q4 2007. Total disk storage systems capacity shipped reach 1,645 petabytes, growing 56.3%.