Mälutükeldust

Mälutükeldust, also known as memory fragmentation, is a phenomenon that occurs in computer memory management. It refers to the state where a block of memory is divided into many small, non-contiguous pieces. When a program requests memory, the operating system searches for a sufficiently large, contiguous block to allocate. If the available memory is fragmented, even if the total free space is enough, the system may be unable to satisfy the request because no single free block is large enough.

Fragmentation can arise from various memory allocation and deallocation patterns. Dynamic memory allocation, where programs repeatedly request and release memory during their execution, is a primary cause. Over time, as these allocations and deallocations occur, free memory can become interspersed with allocated memory, leading to fragmentation.

There are two main types of memory fragmentation: external fragmentation and internal fragmentation. External fragmentation occurs when there is enough total free memory to satisfy a request, but it is not contiguous. Internal fragmentation happens within allocated blocks; for instance, if a program requests 10 bytes of memory, but the system allocates a 16-byte block, the extra 6 bytes are wasted within that block.

To mitigate memory fragmentation, operating systems employ various techniques. Memory compaction is one method, where allocated blocks are moved to consolidate free memory into a single, contiguous chunk. Other strategies include using different memory allocation algorithms, such as first-fit, best-fit, or worst-fit, each with its own trade-offs in terms of speed and fragmentation. Advanced memory management schemes like paging and segmentation also play a role in managing fragmentation.