Micropolis Corp., a Chatsworth-based maker of computer...

Micropolis Corp., a Chatsworth-based maker of computer disk drive data storage products, said it expects to post a “substantial operating loss” for the third quarter because of increased competition and high manufacturing costs. In last year’s third quarter, Micropolis earned $7 million on sales of $75.2 million. Micropolis cited similar problems when it reported sharply lower earnings in this year’s second quarter, and it said the problems would affect its results into 1989.