What is a page table, and what role does it play in memory management?
What is a page table, and what role does it play in memory management?
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07-May-2023
Updated on 08-May-2023
Aryan Kumar
08-May-2023A page table is a data structure used by the operating system to map the virtual memory addresses used by a process to physical memory addresses in the computer's RAM. It is an important component of virtual memory management, temporarily storing part of program memory on a hard drive or solid state drive (SSD), allowing programs to use more memory than is physically available. Make memory available.
In a virtual memory system, a program's memory is divided into fixed-size units called pages. These pages are typically 4 KB in size, but the size can vary depending on system architecture and implementation. Each page has a unique virtual address that programs use to access the page's content. A page table is a data structure that stores the mapping between virtual addresses and physical addresses. When a program accesses a virtual memory address, the operating system uses the page table to determine the physical address of the page and retrieve the contents of the page from physical memory. The page table also stores information about the status of each page. B. Is it currently in use or has it been swapped out to disk?
Page tables are typically managed by the operating system's memory management unit (MMU). MMU is a hardware component that sits between CPU and RAM. The MMU uses page tables to translate virtual memory addresses to physical memory addresses and also performs other memory management tasks such as memory protection and caching. Page tables are an important component of virtual memory management because they allow programs to use more memory than is physically available and ensure that each program has its own isolated memory space. However, the need to translate virtual addresses to physical addresses introduces overhead and exposes attacks such as page table poisoning, where attackers modify page tables to gain unauthorized access to memory.