Neither venture has yet proved a success. Moreover, despite Apple's rapid growth, Mr. Sculley has been faulted for being too slow to respond to an assault on the company by rival computer makers whose machines are powered by Intel Corporation chips and run Microsoft Corporation software. Apple computers are based on the company's own software and use chips from Motorola Inc. Many industry executives say they think Mr. Sculley missed an opportunity in the late 1980's to move Apple's Macintosh software to Intel-based computers before Microsoft was able to popularize its Windows program, which imitates the graphical Macintosh approach to computing. Many analysts also say he was too slow in reducing Apple's prices during the continuing personal computer industry price war, thereby losing valuable market share that the company has yet to reclaim. Mr.