System Architecture 2-23
OnLine User Processes

Figure2-2 illustrates the virtual address space of a user process after the user

process has attached to shared memory. For a detailed discussion of how a

user process attaches to shared memory, refer topage 2-24.

Figure2-2
An example of a
userprocess virtual
address space.
Depending on the
machine, shared
memory is
allocated “above”
or “below” the
value ofSHMBASE.
Unallocated space
OnLine shared-
memory
segments
SHMBASE
Private data
Shareddatabase server code
(C program text)
User process virtual
address space
UNIX memory