08/05/81	mrds.scope

Scope changes:  The scope mode encodings for version 4 databases has changed
for MR9 MRDS.

Previously the values 0, 1, 2 used for the permit and prevent ops in a call to
dsl_$set_scope had meanings of null, retrieve, and update.

Now the encodings have changed.  They are 0, 1, 2, 4, 8 with meanings of null,
read_attr, append_tuple, delete_tuple, modify_attr.  These correspond exactly
to the old (pre MR8) encoding meanings of null, read, store, delete, modify.
The names were changed to agree with the new attribute level security access
operation names.

When MR9 MRDS is installed, version 4 database users will not be able to open
their databases until after they have their database administrator do an
"adjust_mrds_db path -reset" on the database.  This operation will convert the
concurrency control mechanism to use the new scope modes.

Pl1 programs that have been running against version 4 databases using the scope
mode encodings for r-u, rather than r-s-m-d of pre MR8 MRDS will have to be
changed.	The users of exec_coms with mrds_call will not have to change.  The u
encoding will still mean all update operations.  In addition, the encodings for
mrds_call will include a (or s), d, and m.  LINUS users will not notice a
change after the adjust_mrds_db is done.

To see if your database is using the latest version scope modes, the command
"display_mrds_db_status path -long" can be used.	The latest concurrency
control version (for the r-a-m-d modes) is version 5.


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Historical Background

This edition of the Multics software materials and documentation is provided and donated
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as a contribution to computer science knowledge.  
This donation is made also to give evidence of the common contributions of Massachusetts Institute of Technology,
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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 
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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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    Copyright 1972 by Massachusetts Institute of Technology and Honeywell Information Systems Inc.
    Copyright 2006 by BULL HN Information Systems Inc.
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