Method of copying user storage during a fork (FORKCOPY)

FORKCOPY specifies how user storage is to be copied from the parent process to the child process during a fork() system call.

FORKCOPY(COW) specifies that all fork() calls are processed with the copy-on-write mode if the suppression-on-protection (SOP) hardware feature is available. Before the storage is modified, both the parent and child process refer to the same view of the data. The parent storage is copied to the child only if either the parent or the child modifies the storage.

FORKCOPY(COW) causes the system to use the Extended System Queue Area (ESQA) to manage page sharing.

FORKCOPY(COPY) specifies that fork() immediately copies the parent storage to the child, whether the SOP is available or not. Use this option to avoid any additional ESQA use in support of fork.

Follow these guidelines:

Default: COW