Unhappy with how the negotiations were proceeding, he formed On-line Systems to publish the game. On-line Systems became Sierra On-line and Sierra became extremely successful, based largely on their reputation in the graphic adventure genre. While The Prisoner remained Edu-Ware's best-selling individual product during its first two years of business, educational software remained its primary focus. The Compu-Math series, consisting of three programs designed by Steffin and programmed by Mullich for teaching elementary mathematics, unveiled Edu-Ware's vision of teaching by objectives and measuring learning through pretesting and post-testing. The company's educational approach was perfected in 1981 with the release of the first in the Algebra series, in which learners choose the cognitive approach by which they want to learn. The Algebra series greatly surpassed The Prisoner in sales and became Edu-Ware's greatest source of revenue. Despite the company's successes, by 1982 it was obvious to Steffin and Pederson that they could not continue running the company themselves. Rapidly climbing marketing costs and heavier competition from rivals like Davidson & Associates and Spinnaker Software were taking their toll. For the 1.5 million dollar software company to survive, Edu-Ware needed more management strength and expertise. In July 1983 Management Sciences America, then the world's largest independent software manufacturer, announced that it was purchasing Edu-Ware for a combination of cash and MSA stock, valued at $1.5 million, plus a percentage of future earnings. Having previously specialized in mainframe computer software, MSA saw the purchase as its entry into educational software, which it saw as a future growth market. However, the relationship soon soured as Edu-Ware's marketing was taken over by MSA's Peachtree Software accounting software division, and the Edu-Ware brand identity was slowly extinguished. The final straw came when Personal Computing hit the newsstands in October 1984. The issue featured a well-publicized peach-scented insert that unfolded into eight pages, 32-inches wide, displaying a shelf of 67 Peachtree Software products, all in identical packaging. This included 45 Edu-Ware products that were virtually indistinguishable from the accounting software packaging, the only difference being that the Edu-Ware products had the word 'Education' on the box, even for the Edu-Ware games like Prisoner 2. Steffin's protests over how MSA was handling Edu-Ware caused him to be fired in August 1984. The next month, he filed a lawsuit against MSA, claiming the company had violated securities laws in making fraudulent representations to Edu-Ware's stockholders in order to buy