Irvine, Calif.-based Western Digital (NASDAQ:WDC) has a new subsidiary.

On Wednesday, Western Digital announced that it has acquired privately held I/O optimization software maker VeloBit for an undisclosed sum. Western Digital intends to incorporate its new holding into its HGST subsidiary.

In a press release, Western Digital said Lincoln, Mass.-based "VeloBit enhances storage system performance with its software technology by adding a transparent acceleration layer utilizing solid state drives (SSDs) ... dramatically accelerat[ing] applications and increase[ing] server density." The company characterized the acquisition as helping to expand its presence in the enterprise (i.e. corporate, as opposed to consumer) solid-state disk storage market.

Solid-state drives store data on microchips rather than the magnetic platters that power conventional hard drives. They are generally considered faster and more reliable, though at a higher price. The company said the deal builds on its plans to buy data storage device maker sTec Inc. for about $320.7 million in cash.

Investors appear to be responding positively to today's announcement, bidding up Western Digital shares by 0.3% on a rather flat day for the market.

-- Material from The Associated Press was used in this report.