* Pier Carlo Falotti, president of Digital...

* Pier Carlo Falotti, president of Digital Equipment Corp.’s European division since 1985, has resigned and joined ASK Computer Systems Inc. of Mountain View, Calif., as chief executive officer, effective Sept. 1.

ASK is an industrial software company.

Digital has not named a replacement for Falotti.

On Thursday, Digital unexpectedly announced that Kenneth H. Olsen, the company’s founding chairman, will retire Oct. 1.

Falotti, 50, who joined Digital in 1969, had been president of the U.S. minicomputer’s European arm during a period of explosive growth and alliance building.

Falotti, an electrical engineer, will succeed Sandra L. Kurtzig, the ASK founding chairwoman, who left her post as chief executive in 1985 but returned to reorganize the company in 1989.