Operating System Tutorial : operating system overview, memory management, file management, operating system types, batch operating system, time-sharing operating systems, distributed operating system, network operating system, real-time operating system, operating system services, program execution, i/o operation, file system manipulation, communication, error handling, resource management, protection, operating system properties, multitasking, multiprogramming, interactivity, real-time systems, distributed environment, spooling, operating system processes, program process life cycle process control block, process scheduling, process scheduling queues, two-state process model, schedulers, long-term scheduler, short-term scheduler, medium-term scheduler, comparison among schedulers, context switch, scheduling algorithms, first come, first served, shortest job next, priority based scheduling, round robin scheduling, multiple-level queues scheduling, multithreading, difference between process and thread, advantages of thread, kernel level threads, multithreading models, memory management, process address space, static and dynamic loading, static and dynamic linking, swapping, memory allocation, fragmentation, paging, segmentation, virtual memory, i/o hardware, i/o software, file system, security, one time passwords, linux, kernel mode and user mode.