Search results
Results from the WOW.Com Content Network
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.
A memory protection unit (MPU) is a computer hardware unit that provides memory protection. It is usually implemented as part of the central processing unit (CPU). [ 1 ] MPU is a trimmed down version of memory management unit (MMU) providing only memory protection support.
In this matrix example there exist two processes, two assets, a file, and a device. The first process is the owner of asset 1, has the ability to execute asset 2, read the file, and write some information to the device, while the second process is the owner of asset 2 and can read asset 1.
Apple Computer's MultiFinder of 1987 is a more modern use of this technique. Programs shipped with a requested bounds figure stored in the resource fork and the operating system attempted to move the program to an area in memory with that amount free.
Common physical security access control with a finger print A sailor checks an identification card (ID) before allowing a vehicle to enter a military installation.. In physical security and information security, access control (AC) is the selective restriction of access to a place or other resource, while access management describes the process.
Some early Intel 64 processors lacked the NX bit required for W^X, but this appeared in later chips. On more limited processors such as the Intel i386, W^X requires using the CS code segment limit as a "line in the sand", a point in the address space above which execution is not permitted and data is located, and below which it is allowed and executable pages are placed.
Single allocation is the simplest memory management technique. All the computer's memory, usually with the exception of a small portion reserved for the operating system, is available to a single application. MS-DOS is an example of a system that allocates memory in this way. An embedded system running a single application might also use this ...
In computer security, executable-space protection marks memory regions as non-executable, such that an attempt to execute machine code in these regions will cause an exception. It makes use of hardware features such as the NX bit (no-execute bit), or in some cases software emulation of those features. However, technologies that emulate or ...