The impact of competition from peripheral firms on the standards migration efforts by integrated systems firms with de facto standards control is investigated. When systems firms try to migrate their customers to a new standard, they can lose some control over their installed base because they are constrained in their product offerings. Peripherals firms do not face such constraints. Their product offerings allow the emergence of hybrid systems which systems firms are unwilling to match. Improved peripherals from independent firms make these hybrid systems possible. Such hybrid systems lengthen the economic life of the products that make up the existing standard. Historical and empirical evidence from the mainframe computer industry in the 1960s and 1970s illustrates the competition from peripheral firms and their impact on IBM's standards migration efforts. IBM pursued the establishment of a new de facto standard, while independent disk drive manufacturers supplied peripherals that enabled hybrid systems. For the computer mainframe industry, it was shown that those hybrid systems increased the economic life of IBM's older computers, although IBM was able to migrate its customers to the new standard in this case.