... parentAllocate child's stack and user areaFill child's user area from parentAllocate PID for childSet up child to share parent's textCopy page tables for data and stackSet up sharing ... fd is a file descriptor, and offset is a fileoffset.Page frame 3 Page frame2Page frame1Page frame04 .3 BSDkernelTwo-handedclock scanscore mapMain memory Core map entryCore mapentries, ... processes can share a mapped file. System call Descriptions = brk(addr) Change data segment size a = mmap(addr, len, prot, flags, fd, offset) Map a file ins = unmap(addr, len) Unmap a fileFig....