Degrees

Operating systems

Kernel and system calls, processes and threads, scheduling, synchronisation, paging and virtual memory, file systems, I/O and virtualisation.

Course · 8 lessons · 61 min

Taught inComputer ScienceCybersecurity

  1. 1What an operating system doesFreeThe kernel is the one program that may touch the hardware. Everything else asks it, through system calls, and the CPU enforces the rule.1961–today · 7 min
  2. 2Processes and threadsA process is a program in execution with its own address space; threads share it. How Unix creates both, and the states they move through.1960s–today · 7 min
  3. 3CPU schedulingWhich ready process runs next? FCFS, SJF and Round Robin, the metrics that judge them, and a waiting-time exercise worked step by step.1961–today · 8 min
  4. 4Synchronisation and deadlockRace conditions, critical sections, mutexes and semaphores, and the four Coffman conditions that every deadlock satisfies.1965–1971 · 8 min
  5. 5Paging and the TLBEvery address a program uses is virtual. Page tables map it to physical memory, and a small cache, the TLB, keeps that fast.1962–today · 8 min
  6. 6Virtual memory and page replacementPages live on disk until touched. When RAM is full, the OS must evict one: OPT, FIFO, LRU and Clock, with a worked fault count.1962–1969 · 8 min
  7. 7File systems: inodes and journalingHow a disk of numbered blocks becomes named files: inodes, directories, links, indirect blocks, and the journal that survives a power cut.1974–today · 7 min
  8. 8I/O and virtualisationPolling, interrupts and DMA move data between devices and memory; hypervisors then run whole operating systems as guests.1974–today · 8 min