Solid state drives may be the inevitable future of computer storage, but there's still plenty of demand for traditional hard disk drives. In fact there has been no indication of a market slowdown, which has affected the NAND flash industry, but rather a healthy 21% gain in shipments over the same period last year.

According to market research firm iSuppli, 137 million hard drives were shipped during the first quarter of this year, with units primarily being snapped inside notebook PCs, consumer electronics, desktops, and external drives. Vendors saw some healthy operating margins, too. Seagate reported $363 million in profits, or 11.7% of revenue, Western Digital announced $298 million, or a 14% return and Hitachi GST stated it had earned $65 million, or 4.6% of revenue.

It remains to be seen how flash-based storage will affect the HDD industry overtime, but as long as demand for low-cost storage capacity continues to rise, hard drive makers will find ways to stay competitive for some time. iSuppli says vendors are on track to ship 573 million drives by the end of this year, which represents 11 percent growth over last year's final tally.