CISC 324 Lecture Notes - Lecture 3: Page Table, Process State, Memory Management

• School: Queen's University
• Department: Computing
• Course: CISC 324
• Professor: Dorothea Blostein

Document Summary

Pcb (process control block) is an os data structure used to represent a process. Register values for the process (pc, sp, flags, general purpose registers) Memory management registers, base and limit registers or ptbr (page table base register) Pointers to open file (eg unix call "fopen in lab1") Os creates pcb1 and allocates physical memory to store the vm. Keyboard interrupt handler at 0300 rti (return from interrupt) at 03ff. Pc is 0100 in virtual memory = 9100 in physical memory. Timer interrupt handler at 0400 rti at 0600. Pcb2 is in ready queue, saved pc value is b100. Now pc contains 9104 and "check for interrupts" notices a keyboard interrupt. In response, the hardware pushes pc value (9104) Next instruction fetch is executing keyboard interrupt handler. Rti is executed eventually, pop top of the stack into pc. Copy pc value from top of stack into pcb1, copy other register values into pcb1 sp,