DESIGN AND IMPLEMENTATION OF PAGE FRAME ALLOCATION IN AN OPERATING SYSTEM

Abstract

In a memory management system with paging, the entire physical memory is divided in form of page frames. A suitable mechanism is needed to dynamically allocate and deallocate these page frames to various processes as and when needs arise. This dissertation proposes a mechanism for the page frame management and allocation to support virtual addressing in MINIX operating system for Intel 80x86 architecture, from 80386 onwards. The standard MINIX distribution does not support virtual addressing. The proposed design for the memory management system is non-paging (i.e. paging without virtual memory support). This dissertation proposes all the necessary changes that should be made to the memory manager and kernel of MINIX operating system to achieve non-paging. This design uses two level paging system of Intel 80x86 architecture with single page directory for all the processes in the system. As paging unit of base architecture is enabled to support page frame management for virtual addressing in MINIX, page fault may occur. So there is a need to handle the page fault. The dissertation also proposes an exception handler for the page fault. As it is a nonpaging system, page fault handler is simple and it does not need any page replacement algorithm.