Mark Williams Company

This page contains links to material related to Mark Williams Company (MWC). I worked for MWC from 1977 through 1995. I wrote MWC's first software product, the 8080 BASIC interpreter XYBASIC. MWC's most significant product was the Unix look-alike operating system COHERENT. (AT&T was not happy about COHERENT; see 1994 recollections from Dennis Ritchie.)

I was in charge of documentation in the very early days of COHERENT, but the incredibly competent Fred Butzen soon took over from me. In Sept. 2012, fifteen years after MWC's demise, I decided to resurrect and post some COHERENT documentation based on Fred's original sources; see the links below. I hope to post PDF versions of more MWC docs eventually. In the meantime, here are some cover pages.

Each copy of COHERENT came with a hard copy of the manual. My most recent edition is Revision 11, dated 1994, xviii + 1204 pages. It's a wonderful book, generated by a single COHERENT shell script running troff to produce PostScript output; no PDF back then, so we had to print the PostScript on a laser printer to produce a camera-ready hard copy for reproduction. The manual includes several introductory sections (sh, lex, yacc, MicroEMACS, etc.), but most of it consists of a very useful Lexicon. The Lexicon contains over 1200 articles listing COHERENT commands and functions in alphabetical order. These articles were also available as manpages via the COHERENT man command. PDF and PostScript versions of the manual are here.

Most COHERENT commands were modeled on UNIX commands, so their equivalents are still at your fingertips under Linux or Cygwin or a MacOS terminal. Nostalgia motivated me to reimplement a few, listed below, based on the original sources.

In January 2015, Robert Swartz (founder and president of MWC) agreed to open posting of COHERENT command and system sources under an open source license.

This material was originally © Mark Williams Company. It is posted here with the kind permission of my long-time friend and boss Robert Swartz, the current copyright holder.

COHERENT commands:

COHERENT documentation: