Memory Patterns

* Static allocation pattern
pros: deterministic allocation/deallcation time and no memory fragmentation and easy to maintain.
cons: long init time and large mem supply. inflexible.

* Dynamic allocation pattern
pros: flexible, sizable exec
cons: non-deterministic allocation/deallcation time and mem fragmentation. Hard to maintain ptrs mem.

* Pool allocation pattern
pros: more flexible than static allocation to satisfy dynamic requirements. sub deterministic allocation/deallcation time(possible the pool runs out) and no mem fragmentation.
cons: the num of objs in the pool needs to be explored for the best performance of diff systems.

* Fixed sized buffer pattern
pros: no mem fragmentation since it always uses the worst case of mem requirement.
cons: waste mem on average. And it could be improved by managing varied size heaps.

* Smart ptr pattern

* Garbage collection pattern

* Garbage compactor pattern