- Segmentation
- Definition: Dividing a computer’s memory into segments, each of which can be independently protected and managed.
- Purpose: Allows for the organization and isolation of different parts of memory, which helps in preventing one process from interfering with another.
- Protection Keying
- Definition: Assigning numerical values (protection keys) to blocks of physical memory.
- Function: Divides physical memory into blocks, each associated with a protection key. The operating system uses these keys to control access to memory segments, ensuring that only authorized processes can access specific memory blocks.
- Paging
- Definition: Dividing memory address space into equal-sized blocks called pages.
- Purpose: Allows the system to use virtual memory, emulating more RAM than is physically available. The system kernel knows the location of the page file, which is used to store and retrieve pages when needed.
- Data Execution Prevention (DEP)
- Definition: A system-level memory protection feature built into the operating system.
- Function: Prevents code from being executed from data pages, such as the default heap, stacks, and memory pools. DEP helps protect against certain types of attacks, like buffer overflows, by marking areas of memory as non-executable.
These memory protection mechanisms are crucial for maintaining system security, preventing unauthorized access, and ensuring that processes do not interfere with each other. Understanding these concepts is important for the CISSP exam, as they relate directly to system architecture and security controls.