AIX 4.3.3: Have mmap from /dev/zero. Have mmap with MAP_ANON(YMOUS). mmap of /dev/zero works. mmap with MAP_ANON(YMOUS) works. -rw-rw-r-- 1 dje dje 0 Jan 09 12:32 test1a.l -rw-rw-r-- 1 dje dje 0 Jan 09 12:32 test1z.l -rw-rw-r-- 1 dje dje 0 Jan 09 12:32 test2a.l -rw-rw-r-- 1 dje dje 0 Jan 09 12:32 test2z.l David