Tandon said Monday that it has hired...

Tandon said Monday that it has hired its fourth former high-level IBM executive since November.

The latest addition, Joseph A. Sarubbi, 57, was named to the new position of senior vice president of manufacturing operations. He will be in charge of the Chatsworth-based company’s personal-computer and disk-drive manufacturing in the United States and Singapore. Sarubbi had been IBM’s director of technology and systems architecture at the company’s personal computer facility in Boca Raton, Fla.

Tandon executives have been transforming the company from one of the nation’s largest makers of disk drives into a maker of IBM-compatible personal computers. Tandon’s president, Dan H. Wilkie used to head manufacturing and operations at IBM’s Boca Raton site. The other former IBM executives hired recently are H. L. Sparks, Tandon’s senior vice president for sales and marketing, and William L. Sydnes, vice president of engineering and development. Tandon’s founder and chairman, Sirjang Lal (Jugi) Tandon, once worked for IBM.