:PROPERTIES: :ID: 6f77458f-4865-4da5-b6ac-691802b700df :mtime: 20240525073424 20240307034409 20240304105807 :ctime: 20240304105805 :END: #+title: process control block #+filetags: :operatingsystems:public:project: * PCB *PCB* is Data structure representing a [[id:ea9ceb4e-ff99-4939-ad40-90d5dae2d567][process]], containing 8 things 1) *Process ID* – uniquely identifies the process 2) *[[id:64370e0d-7608-44dc-a647-28fe2e3ef3a4][Current process state]]* – running, waiting, etc 3) *CPU scheduling information* – priorities, scheduling queue pointers 4) *Memory-management information* – memory allocated to the process 5) *Accounting information* – CPU used, clock time elapsed since start, time limits 6) *I/O status information* – I/O devices allocated to process, list of open files 7) *Program counter*, location of next instruction to execute 8) *CPU registers*, contents of all process-centric registers. The registers vary in number and type, depending on the computer architecture. They include accumulators, index registers, stack pointers, and general-purpose registers, plus any condition-code information. Along with the program counter, this state information must be saved when an interrupt occurs, to allow the process to be continued correctly afterward