3/15/72                                                 FORK (II)





NAME            fork  --  spawn new process



SYNOPSIS        sys fork  / fork = 2.

                (new process return)

                (old process return)



DESCRIPTION     fork is the only way new processes are created.

                The new process's core image is a copy of that of

                the caller of fork; the only distinction is the

                return location and the fact that r0 in the old

                process contains the process ID of the new pro-

                cess.  This process ID is used by wait.



FILES           --



SEE ALSO        wait(II), exec(II)



DIAGNOSTICS     The error bit (c-bit) is set in the old process

                if a new process could not be created because of

                lack of process space.



BUGS            See wait(II) for a subtle bug in process destruc-

                tion.



OWNER           ken, dmr