Basics of Operating System

Process synchronization refers to the coordination of processes that share resources or need to communicate. It's crucial in concurrent systems where processes may execute simultaneously and interact with shared data.

A critical section is a segment of code in which a process accesses shared resources (like variables, files, or memory). If multiple processes enter their critical sections at the same time, it may lead to inconsistent data or system crashes.

A mutex is a binary lock that allows only one thread/process to access a critical section at a time.

A semaphore is a more general synchronization mechanism, which can be binary or counting.

Scheduling in operating systems refers to the process of deciding which process (or thread) should be executed next by the CPU when multiple processes are ready to run. It is an essential function of the OS to ensure efficient and fair use of CPU time.

CPU Scheduling Algorithms determine the order in which processes in the ready queue are assigned to the CPU for execution. The choice of algorithm affects system performance such as response time, throughput, and CPU utilization.

A deadlock is a situation in an operating system where a set of processes are blocked forever, each waiting for a resource that is held by another process in the same set.

Deadlock prevention ensures that at least one of the four necessary conditions for deadlock (Mutual Exclusion, Hold and Wait, No Preemption, Circular Wait) is never allowed to occur.

Deadlock Detection and Recovery: When a system does not prevent or avoid deadlocks, it must detect them and recover from them to maintain system reliability. This approach is used when deadlocks are rare but possible.

Memory Management is a core function of an operating system (OS) that manages the computer's primary memory (RAM). It involves allocating, tracking, and freeing memory used by processes during execution.

Segmentation is a memory management technique in which the logical address space of a process is divided into segments of different lengths, based on the logical divisions in a program.

Paging is a memory management technique in which the logical address space of a process is divided into fixed-size blocks called pages, and the physical memory is divided into blocks of the same size called frames.

A Page Table is a data structure used in paging to store the mapping between a process's logical pages and physical memory frames. It is maintained by the Operating System and used during address translation from virtual/logical addresses to physical addresses.

Virtual memory is a memory management technique that allows a computer to run programs that are larger than the actual physical memory (RAM). It creates the illusion of a large, continuous block of memory for each process by using a combination of RAM and disk space

Demand Paging is a virtual memory technique where pages are loaded into RAM only when they are needed, not in advance.

Copy-on-Write is a memory optimization strategy where parent and child processes share the same memory pages until one modifies a page. At that point, a copy is made.

When no free frames are available in RAM and a new page must be loaded, the OS uses a page replacement algorithm to decide which page to remove.