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The (h,k)-paging problem is a generalization of the model of paging problem: Let h,k be positive integers such that . We measure the performance of an algorithm with cache of size h ≤ k {\displaystyle h\leq k} relative to the theoretically optimal page replacement algorithm .
The problem of precisely identifying semantic garbage can easily be shown to be partially decidable: a program that allocates an object , runs an arbitrary input program , and uses if and only if finishes would require a semantic garbage collector to solve the halting problem. Although conservative heuristic methods for semantic garbage ...
Data fragmentation occurs when a collection of data in memory is broken up into many pieces that are not close together. It is typically the result of attempting to insert a large object into storage that has already suffered external fragmentation. For example, files in a file system are usually managed in units called blocks or clusters.
In computer operating systems, memory paging is a memory management scheme that eliminates the need for contiguous memory allocation, [1] It is often combined with the related technique of allocating and freeing page frames and storing pages on and retrieving them from secondary storage [ a ] in order to allow the aggregate size of the address ...
Memory management (also dynamic memory management, dynamic storage allocation, or dynamic memory allocation) is a form of resource management applied to computer memory.The essential requirement of memory management is to provide ways to dynamically allocate portions of memory to programs at their request, and free it for reuse when no longer needed.
In computer science, thrashing occurs in a system with virtual memory when a computer's real storage resources are overcommitted, leading to a constant state of paging and page faults, slowing most application-level processing. [1] This causes the performance of the computer to degrade or even collapse. The situation can continue indefinitely ...
In computer operating systems, demand paging (as opposed to anticipatory paging) is a method of virtual memory management. In a system that uses demand paging, the operating system copies a disk page into physical memory only when an attempt is made to access it and that page is not already in memory (i.e., if a page fault occurs).
However, there still exists the problem of internal fragmentation – memory wasted because the memory requested is a little larger than a small block, but a lot smaller than a large block. Because of the way the buddy memory allocation technique works, a program that requests 66 K of memory would be allocated 128 K, which results in a waste of ...