EL SEGUNDO, CA -- Shipments of external hard drives are projected to grow 20% year-over-year in 2009, iSuppli forecasts.

The surge comes despite a predicted 3.5% drop in PC shipments, the market research firm says.

External hard drive shipments have been aided by sales of netbooks, which lack ample storage. Netbook shipments are forecast to grow more than 30% this year and next. The need for memory for digital images and music is another driver, the firm says.