Because no income stream was directly associated with the instructional software, the publisher usually had little motivation to upgrade the software.

Worldware (and student editions) had a number of advantages that rendered them more viable than typical instructional software:

In contrast, when instructional software disappeared, all the instructor's work of curricular revision and skill development became useless.

Not Another Completely Heuristic Operating System, or Nachos, is instructional software for teaching undergraduate, and potentially graduate level operating systems courses.

Mrs. Hollinshead-Strick, 26, was until last month a designer of instructional software at iProgress, a Paris software company.

They provide a large number of workstations equipped with instructional software and information resources tailored to course requirements.

Mr. Hilborn, 33, is a designer of instructional software for Harvard University.

The 438-page book includes descriptions of administrative as well as instructional software.

It combined educational theory and computer programming to supply instructional software.

He has also developed instructional software and interactive Web sites to support teachers and students in using computers and the Internet for education.