Operating Systems (PCCST403) Syllabus

Introduction to Operating Systems, operating system services, overview of operating systems and kernels, Linux versus classic Unix kernels. Process concepts: process creation, process states, data structures, process API, sharing the processor among processes — user and kernel modes, context switching, system boot sequence. Case study: Linux kernel process management. Threads and Concurrency: concept of a thread, multithreading benefits, multithreading models. Case study: the Linux implementation of threads. Process scheduling: concepts and basic algorithms, the multilevel feedback queue. Case study: the Linux Completely Fair Scheduler (CFS), preemption and context switching.

Concurrency and Synchronization: basic principles, mechanisms — locks (the basic idea, building spin locks with test-and-set, compare and swap, using queues), semaphores (definition, binary semaphores, the producer/consumer bounded buffer problem and its solution, reader-writer locks). Case study: Linux kernel synchronization methods — spin locks, semaphores, mutexes. Concurrency: deadlock and starvation — deadlock characterization, prevention and avoidance, detection and recovery; Dining Philosophers problem and its solution.

Memory management: address space, memory API, address translation, dynamic (hardware-based) relocation, segmentation — generalized base/bounds, address translation in segmentation, support for sharing. Virtual memory — paging: introduction, page tables and hardware support, TLBs, TLB hits and misses, handling TLB misses, TLB structure, reducing the page table size. Going beyond physical memory: swap space, page fault and its control flow, page replacement policies, thrashing.

I/O system: modern system architecture, programmed I/O, interrupts, DMA, device interaction methods, the device driver. Hard disk geometry, disk scheduling. Case study: Linux I/O schedulers — Elevator, Complete Fair Queuing. Files and Directories: the file system interface — file descriptor, reading and writing files, hard links and symbolic links, creating/reading/deleting directories, permission bits and access control lists, mounting a file system. File Organization: the inode, the multi-level index. Case study: VFS objects and their data structures.