:PROPERTIES: :ID: ffd6e138-6cc4-450f-b3da-24edf74d4201 :mtime: 20240305025721 :ctime: 20240305025720 :END: #+title: process termination #+filetags: :public:project: * Process Termination There are 3 ways for a [[id:ea9ceb4e-ff99-4939-ad40-90d5dae2d567][process]] to die ** Process performs an illegal operation, e.g., • Makes an attempt to access memory without authorisation • Attempts to execute a privileged instruction ** [[id:9903fd7a-39b0-47c9-adeb-7f98cdefa4d5][Parent]] terminates child (abort, kill), e.g. because • [[id:7405eae1-0686-41c0-a87d-7c402d98e018][Child]] has exceeded allocated resources • Task assigned to child is no longer required • Cascading termination – parent is exiting and OS requires children must also exit ** Process executes last statement and asks the OS to delete it (exit) • Parent waits and obtains status data from child • If parent didn’t wait, process is a zombie • If parent terminated without waiting, process is an orphan