SoftPert Systems, Ltd

Editor: Having worked on real-time expert systems for several years, I read with interest the survey article "Real-Time Knowledge-Based Systems" by Thomas Laffey, et al. in the recent edition of AI Magazine. Indeed, the work of myself and my colleagues was mentioned, but the description of YES/L1 in the article was incorrect in several ways. Laffey and his coauthors incorrectly describe YES/L1 as being "implemented in OPS5 and MacLisp " They seem to be confusing YES/Ll, the shell, with YES/MVS was written in OPS5. YES/L1 is a compiled, data-driven language and an environment for developing interactive and real-time expert systems. The YES/L1 language is an integration of procedural and rule-based techniques.