8. Virtual Memory in Real-Time and Embedded Applications
Virtual memory provides a means for systems to utilize more memory than is physically available by leveraging address translation and paging. While it enhances multitasking and memory protection in general-purpose systems, its use in real-time and embedded systems is limited due to issues like unpredictable latency and increased overhead. Techniques like memory locking and the use of Memory Protection Units (MPUs) can help balance the need for memory flexibility with real-time performance requirements.
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What we have learnt
- Virtual memory allows for greater memory utilization but introduces latency and complexity.
- Embedded systems often avoid full virtual memory due to timing unpredictability, preferring simpler memory management techniques.
- Memory locking and the use of MPUs help enable safe and predictable real-time operations.
Key Concepts
- -- Virtual Address
- Address used by programs to access memory.
- -- Physical Address
- Actual location in hardware memory.
- -- Page Table
- Maps virtual addresses to physical pages.
- -- MMU (Memory Management Unit)
- Hardware component responsible for address translation.
- -- MPU (Memory Protection Unit)
- Provides memory region protection without paging, often used in low-end RTOS systems.
- -- Paging
- Divides memory into fixed-size pages to simplify allocation and protection.
- -- Segmentation
- Divides memory into variable-sized logical segments for tasks like code and data.
- -- Memory Mapping
- Maps files or devices directly into memory space for efficient access.
Additional Learning Materials
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