disk space management

In COWDB2 we should be able to implement a much more scalable and fragmentation resistant memory management system.

First, we can round up allocation requests to the nearest Fibonacci number. This will prevent disk space fragmentation.

Second, we can take a 2-tier approach to space management. The first tier will be a system which is embedded in the root element itself. It will not be scalable and will only be used for managing the space used by the second tier. At issue here is that the root element must not grow beyond an anticipated size.

The second tier will [eventually] be a manager which uses a b-tree. Space for the elements of the b-tree will be managed by the first tier manager, while the second tier manager handles everything else. By using a b-tree for managing space in the second tier manager, we achieve the desired scalability.