08-04-2009, 07:44 AM
In computer science dynamic memory allocation is the allocation of memory storage for use in a computer program during the runtime of that program. It is a way of distributing ownership of limited memory resources among many pieces of data and code. A dynamically allocated object remains allocated until it is deallocated explicitly, either by the programmer or by a garbage collector this is notably different from automatic and static memory allocation. It is said that such an object has dynamic lifetime.
The problem of fulfilling an allocation request, which involves finding a block of unused memory of a certain size in the heap, is a difficult problem. A wide variety of solutions have been proposed, including:
1)Free lists
2)Paging
3)Buddy memory allocation
The main problem for most dynamic memory allocation algorithms is to avoid both internal and external fragmentation while keeping both allocation and deallocation efficient. Also, most algorithms in use have the problem that a large number of small allocations can cause wasted space due to collecting metadata; thus most programmers avoid this, sometimes by using a strategy called chunking.
