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Unlike bytes, larger units can span two aligned addresses and would thus require more than one fetch on the data bus. It is possible for CPUs to support this, but this functionality is rarely required directly at the machine code level, thus CPU designers normally avoid implementing it and instead issue bus errors for unaligned memory access.
At the level of code errors, this occurs when the program writes to part of its own code segment or the read-only portion of the data segment, as these are loaded by the OS into read-only memory. Here is an example of ANSI C code that will generally cause a segmentation fault on platforms with memory protection.
Illegal accesses and invalid page faults can result in a segmentation fault or bus error, resulting in an app or OS crash. Software bugs are often the causes of these problems, but hardware memory errors, such as those caused by overclocking, may corrupt pointers and cause valid code to fail.
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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.
An image of the executable machine code associated with a program. Memory (typically some region of virtual memory); which includes the executable code, process-specific data (input and output), a call stack (to keep track of active subroutines and/or other events), and a heap to hold intermediate computation data generated during run time.
In computing, protected mode, also called protected virtual address mode, [1] is an operational mode of x86-compatible central processing units (CPUs). It allows system software to use features such as segmentation, virtual memory, paging and safe multi-tasking designed to increase an operating system's control over application software.
A general protection fault (GPF) in the x86 instruction set architectures (ISAs) is a fault (a type of interrupt) initiated by ISA-defined protection mechanisms in response to an access violation caused by some running code, either in the kernel or a user program.