Beginning his career as an I.B.M. field service engineer repairing punch card accounting machines in 1951, Mr. Shugart was intimately involved in every important juncture of the computer storage industry for more than four decades. During his 18 years at I.B.M. he managed the development of a number of products, including the I.B.M. 1301, a 50-megabyte disk system that was the basis for Sabre, the nation's first online reservation system, which I.B.M. created for American Airlines. At I.B.M., Mr. Shugart rose to become director of engineering for the systems development division, but left to join Memorex in 1969, eventually taking several hundred I.B.M. engineers with him. In 1972 he left Memorex to found Shugart Associates, which introduced a lower-cost 8-inch form-factor floppy disk drive. Before starting Seagate, Mr. Shugart took a five-year hiatus from the computer industry, having been forced out at Shugart Associates in 1974 after a disagreement with the board. During the break, he moved to Santa Cruz, Calif., where he helped open a bar with friends and bought a fishing boat. In 1979, with Mr. Conner, he returned to the computer storage industry. The two founded Seagate Technology, the first maker of 5.25-inch hard disks, in 1979. Before starting Seagate, Mr. Shugart took a five-year hiatus from the computer industry, having been forced out at Shugart Associates in 1974 after a disagreement with the board. During the break, he moved to Santa Cruz, Calif., where he helped open a bar with friends and bought a fishing boat. In 1979, with Mr. Conner, he returned to the computer storage industry. The two founded Seagate Technology, the first maker of 5.25-inch hard disks, in 1979. Alan Field Shugart studied engineering physics at Redlands University and started work at I.B.M. the day after he graduated. After leaving Seagate, he founded Al Shugart International, a venture capital company. He is survived by his wife, Rita, of Pebble Beach, Calif.; a sister, Margaret Kraght, of Glendora, Calif.; a son, Chris, of Monterey, Calif.; his daughters, Teri, of San Carlos, Calif.; Jill Bambace, of Aromas, Calif.; Mia Peterson of Carmel, Calif.; and Dana Bambace, of Carmel, Calif.; and seven grandchildren.