was assigned both project lead and sole programmer. Despite difficulties with both hardware and software (and some communication delays with IBM), O'Rear produced PC DOS v1.0 in August 1981. The boot sector of the PC DOS v1.0 floppy disk even bears his name, instead of the 'Microsoft Inc' text of subsequent versions. The success of MS-DOS and IBM's branding of it (PC DOS) made Microsoft a Fortune 500 company. Retirement O'Rear retired from Microsoft in 1993. O'Rear started a ranch in the Texas Panhandle where he grew up with his brother. While O'Rear provides the financing and business structure, his brother runs and operates the ranch. He spends more time with his family and pursues his hobbies, including golf, racquetball, and skiing. O'Rear is also a director on several boards of local businesses and invests in real estate development. Just before his retirement, he joined the advisory council on the College of Natural Sciences at the University of Texas at El Paso, his alma mater, through which he keeps a working relationship between the university and Microsoft by encouraging recruit students from the university. See also History of Microsoft Bibliography Tsang, Cheryl D. Microsoft First Generation. Canada: John Wiley & Sons inc., 2000. References External links Microsoft employees DOS people University of Texas at El Paso alumni Living people People from Wellington, Texas Year of birth missing (living people)