15 - Processes Flashcards
What is a process in operating systems?
A process is an active entity representing a program in execution, complete with its own context such as processor state, memory, and I/O resources.
What is the difference between a program and a process?
A program is a passive set of stored instructions, while a process is the active execution of those instructions with its own resources and context.
What information is contained in a Process Control Block (PCB)?
A PCB contains the process ID (PID), current state (running, waiting, etc.), CPU register values, scheduling priority, and I/O resource information.
What are the main stages of a process’s life cycle?
The stages are: New, Ready, Running, Waiting/Blocked, and Terminated.
What are the typical state transitions in a process life cycle?
Transitions include NEW to READY (admission), READY to RUNNING (dispatch), RUNNING to READY (timeout), RUNNING to BLOCKED (waiting for an event), BLOCKED to READY (event occurrence), and RUNNING to EXIT (completion).
How does an operating system support multitasking through process management?
The OS manages multiple processes simultaneously using mechanisms like the Process Control Block and scheduling algorithms to allocate CPU time efficiently.
What is process scheduling, and what are some common scheduling algorithms?
Process scheduling determines which process runs next. Common algorithms include Round Robin, Shortest Job First (SJF), and First-In First-Out (FIFO).
What performance metrics are optimized by process scheduling?
Scheduling optimizes throughput (number of processes completed per unit time) and latency, including turnaround time, response time, and waiting time.
What are the key steps involved in process creation?
Process creation involves assigning a unique PID, allocating memory, initializing the PCB (including state, CPU context, and scheduling parameters), and placing the process in the READY queue.
How do Unix/Linux systems create a new process using fork() and exec()?
In Unix/Linux, fork() duplicates an existing process, and exec() loads a new program into the process’s memory space, allowing the shell to launch commands like ls.
How does process creation in Windows differ from Unix/Linux?
Windows uses CreateProcess, which combines the functionalities of fork() and exec() by creating a new process with its own memory space and specifying the program to run.
What are the primary ways in which a process can terminate?
A process can terminate normally (voluntary exit), due to an error or exception (like a segmentation fault), or be killed by another process (e.g., using kill commands).
What role do signals play in process management?
Signals are used by the OS to facilitate communication between processes, such as sending a termination request (e.g., using kill -9) or other management tasks.
What additional process management tasks are provided by the operating system?
Beyond termination, the OS supports adjusting scheduling priorities (via commands like nice and renice), inter-process communication (IPC), and managing process properties with system calls like getpid() and setpriority().
