Yahoo-Microsoft? No go. Something happening with Facebook? Don't hold your breath. If you want a hot, sexy tech deal, you have to look at data centers.

In the biggest tech acquisition since the $18 billion buyout of Freescale Semiconductor, Hewlett-Packard has agreed to buy Electronic Data Systems for $12.6 billion in cash.

The deal will make Hewlett-Packard a more formidable challenger to I.B.M. for big I.T. corporate and data-processing contracts around the world, a cutthroat business where size can be everything. With E.D.S., Hewlett's annual services revenue will more than double to more than $38 billion.

Corporate data centers may appear to be a business far from Web 2.0 factory smokestacks, but Steve Lohr on the New York Times' Bits blog notes that they may become strategically important.

Rod Bourgeois, a technology-services analyst at Sanford C. Bernstein, tells Bits that data centers are using technologies to become more green and to transform programs to Web-friendly software.

"There's a lot happening in the data center, and being in the middle of that is crucial for H.P.," Bourgeois told Bits.

Hewlett says it will create a new business unit, E.D.S., an H.P. company, which will be based at E.D.S.'s existing headquarters in Plano, Texas. It will be led by the chief executive of E.D.S., Ronald Rittenmeyer.

The combination of H.P. and E.D.S. will create a leading force in global I.T. services," said Mark Hurd, the chief executive of Hewlett-Packard.

The deal is Hewlett's biggest since the merger with Compaq Computer in 2002.

Hewlett is paying $25 per share for E.D.S., or $25.6 billion. The transaction has an enterprise value, which subtracts cash and includes liabilities of $13.9 billion. It is expected to close in the second half of his year.