Review of assembly language. Procedure calls, stacks, interrupts, and traps. Assemblers, linkers, and loaders. Multiprogramming, time sharing, network operating systems, distributed operating systems, and real time systems. Operating systems architecture: monolithic/layered/virtual machine/micro kernels. Linking and loading, shared libraries, swapping. Real memory management: mono-programming, multiprogramming, partitions. Virtual Memory: paging, segmentation. I/O control, device drivers and device independence. File systems: file concepts, directories, file and directory operations, implementation issues, disk space management, file storage, directory structure, file protection. Laboratory to include experiments and exercises in Unix, Linux, and Windows 2000.