An Executive System Implemented as a Finite-State Automaton
The 473L command and control system used by
the Air Force permits many operators to access 
large data files through the use of a computer.  The man-machine
interface is satisfied by several communication 
consoles from which operators may enter queries and
view replies.  A data link permits remote stations 
to send messages, status reports and inventories directly
to the computer.  The information received 
over the on-line data link is used to update the data files
which are stored on disk.  The 473L programming 
system is divided into an Executive Control Program and
five components with different processing priorities. 
 These priorities permit the system to be most sensitive
to the console inputs and permit the operators 
at all the consoles to time share the central processor.
 The Executive Control Program provides for 
the orderly transitions of control among the programming
system components. The major emphasis of the 
paper is on the technique of using the definition of a
finite-state automaton for organizing the Executive 
Control Program.
CACM November, 1964
Heistand, R. E.
