Multics > Library > Source
18 Jul 2023

Old Source Code

Selected Multics Source Programs

(1999) Here is a small selection of nine Multics PL/I and ALM source files, rescued from a mangled copy of the system source formerly hosted at MIT in 1985, corresponding to MR11. These modules are presented for nostalgia and study, and should not be incorporated into any contemporary operating system without the advice of a trained professional.

To explore a complete Multics source library, inlcuding post-Bull development, see Multics Source Code.


The piece of segment control that makes an AST entry for a segment and brings its page table into core.


This piece of the linker is called in response to a linkage fault. It finds the link target and "snaps" the link.


Process Exchange Switch Stack, the Multics scheduler and dispatcher.


Fault Interceptor Module. This program is entered from the hardware fault vector when the CPU takes a fault.


The VTOC manager. See The New Storage System and It Can Be Done for a description of the functions of this module.


The main event loop of the answering service.


An archive containing the source for eight commands and four subroutines involved with presenting information to the user. check_info_segs, help, help_, list_help, list_ref_names, print_motd, resource_usage, ring0_get_, user_info_ system_info_, who, where.


This application program prints a wall calendar. See especially Dennis Capps's lengthy comments on the Easter routine.


A subroutine to print "big letters," used by the I/O Daemon's head and tail page.