Not true. LSX was developed by yours truly during the mid-70's while I was at Bell Labs in Murray Hill. See BSTJ July/August 1978, page 2087-2101. It was developed to support some real-time features like contiguous files and asynchronous I/O. A number of groups in Bell Labs used LSX and added device drivers to support their dedicated applications. Western Electric (WE) was responsible for licensing the UNIX system at the time and only provided source code for the UNIX system for the PDP11 computer with an MMU for $20K. LSX source code was not included in this. I also developed (actually modified and wrote device drivers for) a version of the UNIX system that ran on the PDP11/10 computer, which also did not have an MMU. It could support up to four users. I believe that the source code for this system (Mini-UNIX) was provided to some universities by the UNIX Support group at Bell Labs. WE did not license this. I do not believe that WE ever considered licensing a binary version of LSX or the UNIX System to run on the IBM PC or any other microcomputer. WE only offered binary licenses later on, and then only for the PDP11 with an MMU first. In hindsight, a missed opportunity, but that's another story. Doug may be able to offer some insight into this as well. Thanks for asking, Heinz Lycklama On 2/21/2020 2:37 AM, Ed Bradford wrote: > I also worked with LSX - a stripped down version of Unix that required > no MMU. It worked on a PDP 11/03 and we delivered an LSX product to > the telco's based on LSX. My faulty memory tells me Mike Lesk created > LSX. Is that true? > > Did BTL/AT&T ever try to sell LSX to IBM for its 1981 intro of the IBM PC? > > Ed Bradford, BTL 1976-1983 > Columbus and Whippany