Question 1: Does anyone have an idea of how to reach A. J. Critchlow (or if he is still alive)? He was with IBM San Jose when his paper Generalized Multiprocessing and Multiprogramming Systems was published in the proceedings of the AFIPS 1963 Fall Joint Computer Conference. This was in a conference session that also included a paper by Melvin Conway entitled A Multiprocessor System Design. Both papers mention the computer operating system function of Fork (in the sense of fork-and-join). In particular, the Conway paper describes the capability in a way somewhat like the later implementation for the SDS940 time-sharing system. The Conway paper also notes three operating systems he had heard had something like the fork capability. Question 2: Does anyone know of any *earlier* references in the literature to the work Fork used in this sense, or early operating system which had this capability. I am asking these questions on behalf of Linus Nyman who wrote his dissertation on forking in a difference sense -- branches of work in the software development process. [Understanding Code Forking in Open Source Software – an examination of code forking, its effect on open source software, and how it is viewed and practiced by developers”: https://helda.helsinki.fi/handle/10138/153135 ] Linus has already asked the second question of various computer historians and early operating system developers. So he doesn't need pointers to people of whom he might ask that question. However, perhaps this much larger SIGCIS group of people might include individuals who might have a clue about about Critchlow or themselves have insight to pre-Critchlow-and-Conway references to forking in the literature. Thanks, Dave