Guardian Procedure Calls Reference Manual

• Swap file extent allocation
If an extensible segment is being created, then only one extent of the swap file is allocated
when SEGMENT_ALLOCATE_CHKPT_ returns.
• Segment sharing
Subject to security requirements, a process can share a segment with another process running
on the same processor. For example, process $X can share a segment with any of these
processes on the same processor:
◦ Any process that has the same process access ID (PAID)
◦ Any process that has the same group ID, if $X is the group manager (that is, if $X has a
PAID of group,255)
◦ Any process, if $X has a PAID of the super ID (255,255)
If processes are running in different processors, they can share a segment only if the security
requirements are met and the segment is a read-only segment.
Callers of [CHECK]ALLOCATESEGMENT can share segments with callers of
SEGMENT_ALLOCATE_[CHKPT_]. High-PIN callers can share segments with low-PIN callers.
• Sharing flat segments
A process cannot share a flat segment with a process that allocated a selectable segment,
because the segments reside in different parts of memory. (Similarly, a process cannot share
a selectable segment with a process that allocated a flat segment.)
SEGMENT_ALLOCATE_CHKPT_ Procedure 1275