Zoroaster: A multiprogramming system for psychological research

The development of a multiprogramming system for psychological research was undertaken on a PDP-9 computer with 8k memory. The needs of the users and the time demands on the computer raised several important questions: (1) Can a practical timesharing system be developed with only 8k memory? (2) Can critical timing functions be maintained? (3) Can easy access be provided (e.g., Fortran) to all experimental devices? (4) Can a system be designed which will take advantage of and be compatible with most of the standard DEC-provided software (e.g., Fortran compiler, loader)? The system was successfully developed by using a rapid within-core swapping technique, standard I/O routines, many general-purpose handlers and subroutines, and fully utilizing available core.