Stack versus heap, reference counting, mark and sweep, generational GC, manual management, leaks and fragmentation.
35 cards · basic cards · AI-written, checked twice. Edit anything.
- What is the stack in memory management?
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A region of memory that stores local variables and function call information, following LIFO order.- What does LIFO mean in the context of the stack?
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Last In, First Out - the most recently added item is removed first.- When are stack variables automatically freed?
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When the function they are declared in returns or exits its scope.- What causes a stack overflow?
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Allocating more memory on the stack than its fixed size allows, often due to excessive recursion or large local arrays.- Where are local variables typically stored?
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On the stack, where they are automatically deallocated when their function exits.- What is the heap in memory management?
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A large, dynamically-allocated region of memory used for objects whose size or lifetime cannot be determined at compile time.- Why is heap allocation slower than stack allocation?
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The heap requires dynamic memory management via algorithms like searching for free blocks, whereas the stack uses simple pointer arithmetic.- What is external fragmentation on the heap?
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Gaps of unused memory scattered throughout the heap between allocated blocks, making it hard to find contiguous free space.- Can objects on the heap be automatically freed without garbage collection?
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No, they persist until explicitly deallocated or collected.- What is internal fragmentation?
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Wasted memory within an allocated block due to the block being larger than the object it holds.- How does reference counting work?
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Each object maintains a count of how many pointers reference it; when the count reaches zero, the object is freed.- When is an object freed in reference counting?
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Immediately when its reference count drops to zero.- What is the circular reference problem in reference counting?
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Two or more objects that reference each other form a cycle where counts never reach zero, causing a memory leak even with reference counting.- What is the overhead of reference counting?
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Every pointer assignment requires incrementing or decrementing a count, consuming CPU time and potentially adding cache misses.- Must reference count operations be atomic in concurrent systems?
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Yes, to prevent race conditions from multiple threads accessing the same count simultaneously.
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