Interactive System Productivity Facility - An IBM licensed program that serves as a full-screen editor and dialogue manager. Used for writing application programs, it provides a means of generating standard screen panels and interactive dialogues between the application programmer and terminal user.

Interactive System Productivity Facility. A menu-driven, full screen interface to the most commonly accessed TSO features. It includes facilities to edit, browse, and manage data and programs.

a program development tool designed to increase productivity in a TSO environment

Incremental Shortest Path First (SPF).