J06.12 Release Version Update Compendium

2 Operating System
Open System Services Shared Memory Segments
Beginning with the J06.12 RVU:
• Guardian processes can access shared memory segments using Open System Services functions
such as shmat(), shmget(), shmdt(), and shmctl(). When a Guardian process uses
one of these functions, the Guardian PIN is used in place of the Open System Services pid.
• The size and number of these shared memory segments are restricted by available system
resources only.
• If rounding is requested, user-supplied addresses to the shmat() function are rounded to a
multiple of 4MB. If no rounding is requested, user-supplied addresses to the shmat() function
must be in multiples of 16KB.
For more information about Open System Services shared memory segments, see the Open System
Services Programmer's Guide.
Migration Considerations
None.
Fallback Considerations
Applications with Guardian processes that use the new shared memory segment feature are not
compatible with RVUs prior to J06.12. Customers must fallback to the pre-J06.12 versions of
applications that conform to the features, limits and rules in effect for the older RVUs.
File Security and Umask for OSS Product Files
Open System Services directory and file permissions as delivered have been made more consistent.
In most cases, they now are set to 755; some directories and files have more restrictive permissions.
The default umask setting is now 022.
Migration Considerations
None.
Fallback Considerations
None.
Open System Services Shared Memory Segments 11