This post describe two fundamental kernel resources, paged pool and nonpaged pool, that serve as the memory resources that the operating system and device drivers use to store their data structures. The pool manager operates in kernel mode, using regions of the system’s virtual address space (described in the Pushing the Limits post on virtual memory) for the memory it sub-allocates. The kernel’s pool manager operates similarly to the C-runtime and Windows heap managers that execute within user-mode processes.  Because the minimum virtual memory allocation size is a multiple of the system page size (4KB on x86 and x64), these subsidiary memory managers carve up larger allocations into smaller ones so that memory isn’t wasted.[…]

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