Troubled computer maker Silicon Graphics Inc. said today that Richard Belluzzo, who was brought in less than two years ago to oversee its turnaround, has resigned as chief executive to join another company.

SGI named Robert Bishop, an SGI board member and former executive with the company, to succeed Belluzzo.

"It was a surprise to the company. It certainly was not anticipated," Bill Kelly, SGI's senior vice president of corporate operations, said during a conference call after the changes were announced.

Kelly said Belluzzo left to accept a "noncompetitive, non-CEO position with another company," but he declined to elaborate.

Belluzzo's departure comes at a critical time for SGI, which has struggled to compete with lower-priced computer makers and turn its state-of-the-art graphics-computing technologies into viable commercial products.

Earlier this month, the Mountain View, Calif.-based company announced its second revamping in two years, saying it would cut up to 17 percent of its work force, spin off certain divisions and focus on a few core markets.

During today's conference call, Bishop said that as an SGI board member he had helped formulate the latest turnaround strategy and would now work to get up to speed on its particulars.

"I chose the job because it's probably the most exciting challenge I've ever been faced with," Bishop said. "I feel like I've trained for 35 years in preparation for it."

Bishop joined SGI in 1986 and was responsible for building its international division. He joined the company's board in 1993 and remained an active member of management through 1995. He serves as a member of the Industry Advisory Commission as well as the World Intellectual Property Organization and the board of governors of the World Economic Forum for Information Technologies.

Kelly said SGI learned of Belluzzo's decision to resign today and moved swiftly to name a successor because it was felt that the company "could not afford an extended period of interim leadership."

He said SGI had no intention of putting itself up for sale and had sought assurances from other top executives, including its chief financial officer, Steve Gomo, that they were committed to the company for the long term.

Belluzzo came to SGI in 1998 from Hewlett-Packard Co., where he had often been regarded as heir apparent to chief executive Lew Platt. The job as new Hewlett-Packard chief executive recently went to Carly Fiorina from Lucent Technologies Inc.

Although SGI makes advanced graphics technology used to create movie special effects and for design and simulation in other industries, its machines served more of a niche than a mainstream market. A new line of lower-priced workstations introduced under Belluzzo's leadership has not been as well received as had been hoped.

Bishop repeated that the company's latest turnaround would focus on high-performance servers, visual computing products and broad-band Internet computing products, with a heavy focus on joint development and partnerships, to ease development costs.

While analysts have generally applauded the company's strategy, they have cautioned it will be difficult to execute.

CAPTION: Richard Belluzzo, CEO since last year, will join "another company."