Chapter 3: Processes: Scheduling, IPC, and Client-Server Communication

The chapter defines a process as a program in execution, composed of the program code, current activity (program counter, registers), and associated resources. It begins by explaining the various process states—new, ready, running, waiting, and terminated—along with the process control block (PCB) structure used to store process-specific data like CPU registers, memory management information, and accounting details. The discussion then turns to process scheduling, including long-term, medium-term, and short-term scheduling, as well as CPU–I/O burst cycles that guide scheduling decisions. Context switching, its overhead, and its role in multitasking environments are explained in detail. The chapter also covers process creation and termination, parent–child relationships, and cascading terminations, along with the distinction between independent and cooperating processes. Interprocess communication (IPC) is presented through both shared memory and message-passing models, highlighting synchronization challenges and solutions. Examples of IPC mechanisms, such as pipes and sockets, are provided. The chapter concludes with a look at client–server communication in distributed environments, including socket-based communication and the use of remote procedure calls (RPCs). By the end, readers gain a clear understanding of how processes are represented, managed, scheduled, and coordinated to enable efficient, concurrent program execution.