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Memory protection is a way to control memory access rights on a computer, and is a part of most modern instruction set architectures and operating systems.The main purpose of memory protection is to prevent a process from accessing memory that has not been allocated to it.
VLSI VI475 MMU Apple HMMU from the Macintosh II used with the Motorola 68020. In some cases, a page fault may indicate a software bug, which can be prevented by using memory protection as one of key benefits of an MMU: an operating system can use it to protect against errant programs by disallowing access to memory that a particular program should not have access to.
Through paging, system software can restrict and control a task's access to pages, which are sections of memory. In many operating systems, paging is used to create an independent virtual address space for each task, preventing one task from manipulating the memory of another. Paging also allows for pages to be moved out of primary storage and ...
In computer operating systems, memory paging (or swapping on some Unix-like systems) is a memory management scheme by which a computer stores and retrieves data from secondary storage [a] for use in main memory. [1] In this scheme, the operating system retrieves data from secondary storage in same-size blocks called pages.
Memory management (also dynamic memory management, dynamic storage allocation, or dynamic memory allocation) is a form of resource management applied to computer memory.The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed.
Unlike virtual storage—paging or segmentation, rollout/rollin does not require any special memory management hardware; however, unless the system has relocation hardware such as a memory map or base and bounds registers, the program must be rolled back in to its original memory locations. Rollout/rollin has been largely superseded by virtual ...
In computing, an input–output memory management unit (IOMMU) is a memory management unit (MMU) connecting a direct-memory-access–capable (DMA-capable) I/O bus to the main memory. Like a traditional MMU, which translates CPU -visible virtual addresses to physical addresses , the IOMMU maps device-visible virtual addresses (also called device ...
(Optional expanded memory hardware can add bank-switched memory under software control.) Intel retroactively named the sole operating mode of these x86 CPU models " real mode ". The Intel 80286 and later processors add "286 protected mode ", which retains 16-bit addressing, and adds segmentation (without paging) and per-segment memory protection.