About The who command is derived from the CTSS command of the same name. It lists the users logged in.
Source is available online.
The various daemons are connected to the system via the message coordinator . For example, limited service subsystem users might be assigned a load of 0.5. The header consists of the system name, the total number of users, the current system load, the maximum load, the current number of absentee users, and the maximum number of absentee users. Project.id lists users with the specified person and project. Not allowed for the active function.