Al Shugart, the flamboyant co-founder of Seagate Technology LLC who once ran his Bernese mountain dog Ernest for Congress, died Tuesday in a Monterey hospital following complications from heart surgery he had six weeks ago. He was 76.
 

Mr. Shugart is considered one of the fathers of the computer disk drive, placing him in a pantheon of Silicon Valley luminaires.
 

Alan F. Shugart was born in Los Angeles in 1930 and received a bachelor's degree in engineering physics from the University of Redlands in San Bernardino County.
 

He was an engineer at IBM during the 1960s and helped develop the drives, which were subsequently improved on and used as a relatively cheap and efficient way for storing data on millions of personal and business computers.
 

In 1979, Mr. Shugart founded Seagate Technology, a Scotts Valley manufacturer of hard drives. Under his leadership, the company grew into a dominant supplier of drives for mainframe computers, employing thousands of people across the globe.
 

His tenure at Seagate was also marked by a series of class action suits, including one that the company settled for $5 million. The company was accused in the suit of inflating sales by claiming to have sold disk drives that were actually stored in warehouses. In 1998, during a slump in sales, mounting losses and depressed stock price, he was fired by the Seagate board of directors.
 

Mr. Shugart's career started in 1951 at IBM in San Jose where he ultimately served as director of engineering. His big breakthrough came in 1969 leading a team of engineers that developed the floppy disk, a revolutionary innovation that has become a steppingstone to the comparatively massive memory in computers today.
 

He later took jobs at Memorex Corp., in Sunnyvale, where he was a vice president, and then founded his own company, Shugart Associates, where he was forced out after five years.
 

During his career, Mr. Shugart earned a reputation as a maverick -- at some times a jokester and at other times ornery -- who wore colorful Hawaiian shirts to work and ran his dog for election as way to express his frustration with the political system. He chronicled his dog's losing campaign in a book titled "Ernest Goes to Washington (Well, Not Exactly)," one of three books Mr. Shugart wrote.
 

Bill Watkins, Seagate's chief executive, said in a statement: "It is impossible to summarize the profound impact of Al's work during his 50-year career, most notably of course as a pioneer in the storage industry and Seagate's founder. It was Al's vision and entrepreneurial spirit that turned an emerging technology built with Dixie cups and pantyhose into a universally embraced product that touches so many people around the globe."
 

In recent years, Mr. Shugart was president and chairman of Al Shugart International, a venture capital firm in Santa Cruz that invested in technology startups.
 

He is survived by his wife Rita, four daughters, one son and seven grandchildren.