memory protection (redirected from Protected memory)

memory protection

A technique that prohibits one program from accidentally clobbering another active program. Using various different techniques, a protective boundary is created around the program, and instructions within the program are prohibited from referencing data outside of that boundary.

When a program does go outside of its boundary, DOS, Windows 3.x, Windows 95/98 and earlier personal computer operating systems simply lock up (crash, bomb, abend, etc.). Operating systems such as Unix, OS/2 and Windows NT, 2000 and XP are more robust and generally allow the errant program to be closed without affecting the remaining active programs.

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(memory management)

memory protection - A system to prevent one process corrupting the memory (or other resources) of any other, including the operating system. Memory protection usually relies on a combination of hardware (a memory management unit) and software to allocate memory to processes and handle exceptions. The effectiveness of memory protection varies from one operating system to another. In most versions of Unix it is almost impossible to corrupt another process' memory, except in some archaic implementations and Lunix (not Linux!). Under Microsoft Windows (version? hardware?) any 16 bit application(?) can circumvent the memory protection, often leading to one or more GPFs. Currently (April 1996) neither Microsoft Windows 3.1, Windows 95, nor Mac OS offer memory protection. Windows NT has it, and Mac OS System 8 will offer a form of memory protection.