/* BEGIN INCLUDE FILE dm_cm_basic_ci.incl.pl1 */ /* DESCRIPTION: The collection_manager_ manages the structure of the addressable portion of a control interval. The addressable portion is that portion of a control interval which the file_manager_ will allow the collection_manager_ to address. In this description control interval will be used to mean the addressable portion of a control interval. A control interval is divided into four parts: the header, the datum position table (also known as the slot table or slots), un-used space and used space. The beginning of the header is at offset 0, and the end of the used space is at the end of the control interval (curently offset 4072). Pictoriarly, a control interval is structured as follows: ---------------------------------------------------------------------- | || | | | | | || || | / / | |/| | | | Header || | slot | || un-used space || |/ / /| |/| | | | || | table | || || | / / | |/| | | | || | | | | | || || |/ / /| |/| | | ---------------------------------------------------------------------- ^ ^ ^ ^ ^ ^ ^ | | | | | | | | |...........|.......|...| start of used space| | | | | | each| scattered free space| is a used datum The basic_control_interval structure describes the header (basic_control_interval.header, bci_header) and the slots (basic_control_interval.datum_position_table, datum_slot for one only). Each datum_slot contains the offset (in bytes) and the length (in bits) of a datum in the used space. If the offset is equal to FREE_SLOT (declared in dm_cm_basic_ci_const.incl.pl1), the slot is un-used. The slot also contains flags describing the type of datum (see dm_cm_datum.incl.pl1). */ /* HISTORY: Written by Matthew Pierret, 02/07/82. Modified: 03/25/82 by Matthew Pierret: Fixed alignment differences basic_control_interval and its sub-structures. 06/14/82 by Matthew Pierret: Removed common header and buffers. Changed basic_ci_header to bci_header. Added previous_control_interval. 07/12/82 by Matthew Pierret: Changed collection_id to be bit (36) aligned. 10/29/82 by Matthew Pierret: Added flags to datum slots. 11/10/82 by Matthew Pierret: Removed continued_datum_is_present flag, as it is not used. 03/28/84 by Matthew Pierret: Added the constants BCI_HEADER_LENGTH_IN_BYTES and DATUM_POSITION_TABLE_OFFSET_IN_BYTES. */ /* format: style2 */ dcl 1 basic_control_interval aligned based (basic_control_interval_ptr), 2 header like bci_header, 2 datum_position_table (0 refer (basic_control_interval.number_of_datums)) like datum_slot; dcl 1 bci_header aligned based (bci_header_ptr), 2 layout_type char (4) aligned, 2 collection_id bit (36) aligned, 2 next_control_interval fixed bin (24) uns unal, 2 previous_control_interval fixed bin (24) uns unal, 2 flags unal, 3 continuation_datum_is_present bit (1) unal, 3 free_slot_is_present bit (1) unal, 3 must_be_zero bit (4) unal, /* reserved */ 2 scattered_free_space fixed bin (17) unal, 2 start_of_used_space fixed bin (17) unal, 2 number_of_datums fixed bin (17) unal; dcl 1 datum_slot aligned based (datum_slot_ptr), 2 flags unal, 3 special_format_datum bit (1) unal, /* reserved */ 3 is_continued bit (1) unal, 3 is_continuation bit (1) unal, 3 mbz bit (1) unal, /* reserved */ 2 offset_in_bytes fixed bin (15) uns unal, 2 length_in_bits fixed bin (17) uns unal; dcl basic_control_interval_ptr ptr; dcl bci_header_ptr ptr; dcl datum_slot_ptr ptr; dcl BASIC_CI_LAYOUT_1 char (4) aligned init ("bci1") internal static options (constant); /* END INCLUDE FILE dm_cm_basic_ci.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 */