On 15 Jan, 2007, at 18:00, cctalk-request at classiccmp.org wrote: 1) To prevent one process overwriting the memory belonging to another process. Segments did not HAVE to be 64k, that was their maximum size, the minimum was 128 bytes. 2) To provide virtual memory. 3) To protect the executive from processes. 4) To allow non contiguous physical address space to appear as a logical contiguous address space 5) To provide mapping out of faulty blocks of memory and probably as many reasons I have not thought of off the top of my head. Best regards, Roger.