I review the history and evolution of memory management in MS-DOS on x86 PC architecture. 0:00 Introduction/terminology. 0:53 Origins of MS-DOS. 1:33 8086, 80286, 80386 memory model. Real/protected modes. 3:17 PC address space. DOS address space and memory terminology. 6:46 Expanded memory. 8:26 Extended memory. 10:18 DOS Extenders. 11:35 Microsoft moves to Windows. 12:21 Conclusion.