1. A method for allocating a memory block, comprising the steps of: determining the size of a requested memory block; allocating a memory block directly from an operating system if it is determined that the memory block is a predetermined large size; allocating a memory block from an active memory super-block if it is determined that the memory block is a predetermined regular size; allocating a memory block from a partial super-block if the step of allocating a memory block directly from the active memory block fails; allocating a memory block from a new super-block if the step of allocating a memory block from the partial super block fails; and returning the memory block in response to the request;