01
Processes and Threads
A process represents a running program together with its address space and operating-system-managed resources. Threads provide multiple independently scheduled execution paths within a process.
02
Virtual Memory
Virtual memory gives programs an abstract address space while the operating system and hardware translate virtual addresses to physical memory.
- Isolation prevents ordinary processes from directly modifying each other's memory.
- Paging divides virtual and physical memory into fixed-size units.
- Page tables represent address translations.
- Caching through the translation lookaside buffer accelerates repeated translations.
03
File Systems
File systems organize persistent storage into files, directories, metadata, allocation structures, and consistency mechanisms.
04
Concurrency
Operating systems coordinate concurrent activities using scheduling, synchronization primitives, locks, semaphores, condition variables, and atomic operations.