Once a "command" has been invoked, you can interrupt its operation by
pressing the BREAK key.  After the command has stopped, Multics returns to
"command level."  But this is command level 2.

     While you are at this level, you can resume operation of the command by
issuing the start command.  You can also use the
program_interrupt (pi for short) command when you interrupt operation of certain
editors, like emacs, qedx, and ted, or programs that interact with you by
asking you to supply information as you go.  If by chance you use
program_interrupt with a command that cannot be restarted by it, a message to
that effect will be printed.

     This command, unlike start, accomplishes what you probably want when you
press BREAK: it aborts the most recent action and returns to the previous
level.

     If you do not wish to restart the command you interrupted, you should
issue the release command before issuing any other commands.  That will
return you to level 1, the regular command level.


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Historical Background

This edition of the Multics software materials and documentation is provided and donated
to Massachusetts Institute of Technology by Group BULL including BULL HN Information Systems Inc. 
as a contribution to computer science knowledge.  
This donation is made also to give evidence of the common contributions of Massachusetts Institute of Technology,
Bell Laboratories, General Electric, Honeywell Information Systems Inc., Honeywell BULL Inc., Groupe BULL
and BULL HN Information Systems Inc. to the development of this operating system. 
Multics development was initiated by Massachusetts Institute of Technology Project MAC (1963-1970),
renamed the MIT Laboratory for Computer Science and Artificial Intelligence in the mid 1970s, under the leadership
of Professor Fernando Jose Corbato. Users consider that Multics provided the best software architecture 
for managing computer hardware properly and for executing programs. Many subsequent operating systems 
incorporated Multics principles.
Multics was distributed in 1975 to 2000 by Group Bull in Europe , and in the U.S. by Bull HN Information Systems Inc., 
as successor in interest by change in name only to Honeywell Bull Inc. and Honeywell Information Systems Inc. .

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Permission to use, copy, modify, and distribute these programs and their documentation for any purpose and without
fee is hereby granted,provided that the below copyright notice and historical background appear in all copies
and that both the copyright notice and historical background and this permission notice appear in supporting
documentation, and that the names of MIT, HIS, BULL or BULL HN not be used in advertising or publicity pertaining
to distribution of the programs without specific prior written permission.
    Copyright 1972 by Massachusetts Institute of Technology and Honeywell Information Systems Inc.
    Copyright 2006 by BULL HN Information Systems Inc.
    Copyright 2006 by Bull SAS
    All Rights Reserved