FRAGMENTATION External Fragmentation-total memory space exists to satisfy a request,but it is not contiguous o Internal Fragmentation-allocated memory may be slightly larger than requested memory;this size difference is memory internal to a partition,but not being used o Reduce external fragmentation by compaction ● Shuffle memory contents to place all free memory together in one large block Compaction is possible only if relocation is dynamic, and is done at execution time ·I/O problem o Latch job in memory while it is involved in I/O o Do I/O only into OS buffersFRAGMENTATION  External Fragmentation – total memory space exists to satisfy a request, but it is not contiguous  Internal Fragmentation – allocated memory may be slightly larger than requested memory; this size difference is memory internal to a partition, but not being used  Reduce external fragmentation by compaction  Shuffle memory contents to place all free memory together in one large block  Compaction is possible only if relocation is dynamic, and is done at execution time  I/O problem  Latch job in memory while it is involved in I/O  Do I/O only into OS buffers