Why Dynamic Arrays Aren't Actually Dynamic

TL;DR: Standard arrays are fixed-size by design to ensure O(1) access. Dynamic arrays manage this constraint by over-allocating memory and periodically resizing. By growing the backing array geometrically—usually 1.5x or 2x—the expensive O(n) copy operations are rare enough that the average cost per insertion remains O(1), a concept known as amortized constant time. I often find that one of the first abstractions we take for granted as engineers is the dynamic array. Whether you are using an ArrayList in Java or a standard array in JavaScript, it is easy to assume these structures just "grow" naturally. In reality, memory is still a rigid series of fixed slots. I want to look at how we maintain the abstraction of contiguous growth while staying within the physical limits of memory allocation. Why are standard arrays fixed-size? I look at standard arrays as fixed-size blocks because the operating system requires a contiguous chunk of memory to provide O(1) random access. If I want to ca