/* BEGIN INCLUDE FILE dm_cm_reservation_map.incl.pl1 */

/* DESCRIPTION:

        The collection_manager_'s file reservation map is used to keep track of
   those control intervals which have been reserved by a collection so that
   more than one collection in a file do not attempt to use the same control 
   interval.  Logically the file reservation map is one long bit string
   containing a bit for each control interval of the file.  If the bit for
   a control interval is "1"b, that control interval has been reserved.
   Actually the map is divided into several fragments represented by 
   file_reservation_map_fragment structures, each a bit string of uniform
   length and each stored as an element in the Header Collection.  Ideally,
   each fragment is stored in a different control interval of the Header 
   Collection for enhanced concurrent access to the map.
   
        To increase speed of reference and concurrent throughput the fragments
   are not chained together, but are kept track of by the file_reservation_map
   structure.  This structure is an array with each entry describing the
   location of a fragment, the number of the control interval for which the
   first bit in the fragment represents, and a flag which, if on, indicates 
   that there are no unreserved control intervals in the fragment.  This flag
   allows for skipping looking at fragments which are already full.
*/

/* HISTORY:
Written by Matthew Pierret, 2/23/83.
Modified:
09/24/84 by Matthew Pierret: Added DESCRIPTION section.
*/

/* format: style2,ind3,ll79 */

     dcl	   1 file_reservation_map (frm_number_of_fragments) aligned
			      based (file_reservation_map_ptr),
	     2 flags	      unal,
	       3 no_control_intervals_are_available
			      bit (1) unal,
	       3 must_be_zero     bit (11) unal,
	     2 lowest_numbered_control_interval
			      fixed bin (24) uns unal,
	     2 element_id	      bit (36) aligned;

     dcl	   file_reservation_map_fragment
			      aligned
			      based (file_reservation_map_fragment_ptr)
			      bit (frmf_number_of_control_intervals);


     dcl	   file_reservation_map_ptr
			      ptr;
     dcl	   frm_number_of_fragments
			      fixed bin (17);

     dcl	   file_reservation_map_fragment_ptr
			      ptr;
     dcl	   frmf_number_of_control_intervals
			      fixed bin (17);


/* END INCLUDE FILE dm_cm_reservation_map.incl.pl1 */


*/
                                          -----------------------------------------------------------


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. .

                                          -----------------------------------------------------------

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

*/