Dell Inc deserves more credit for a gradual but steady transformation from its roots as a computer maker into a full-service technology vendor, an overhaul that will take time, its CEO said.

Nearly four years into his second stint as chief of the company he founded, Michael Dell said Dell is becoming more diversified, and aims to be a major player in both data center equipment and the fast-growing mobile market.

Five or 10 years ago people would say Dell is a PC company. Well, news flash -- most of our margin and profit doesn't come from PCs. I don't think people get that, Dell said in a rare exclusive interview on Thursday.

Margins are going in the right direction, the mix of the business is shifting in a pretty considerable way, the picture is starting to emerge more clearly what Dell is becoming.

In a major move to advance its transformation into a one-stop technology shop, Dell announced on Thursday it is bidding for storage specialists Compellent Technologies Inc in a deal valued at close to $1 billion.

The CEO who started out upgrading PCs from his college dorm room acknowledged that plenty of work still lay ahead to compete with rivals like International Business Machines Corp, Hewlett Packard Co and Apple Inc.

It takes time, but clearly the company is changing.

Dell was presiding over an event at corporate headquarters to promote what he sees as a major opportunity selling equipment and services to small- and medium-sized businesses, a segment often overlooked by investors but which makes up roughly a quarter of sales and a third of operating income.

Dell has an enormous channel that can sell to these customers, and this is also where all the growth is, said Dell, who founded the company in the 1980s while still a college student. He stepped down as CEO in 2004, but returned in early 2007 to try and revive his company, which remained too dependent on PC sales as the market matured.

(Reporting by Gabriel Madway; Editing by Richard Chang)