Hi Gina! JCL stands for Job Control Language and is basically the MPE operating system commands and some flow control (IF/THEN/ELSE) functions. It is used to write batch job scripts, online User Defined Commands (UDC's) and Command Files (under MPE/iX). Hope this helps. Jim Phillips Manager of Information Systems E-Mail: [log in to unmask] Therm-O-Link, Inc. Phone: (330) 527-2124 P. O. Box 285 Fax: (330) 527-2123 Garrettsville, Ohio 44231