1. In a computer system having an operating system and a compressed main memory defining a physical memory and a real memory characterized as an amount of main memory as seen by a processor, and including a compressed memory hardware controller device for controlling processor access to said compressed main memory, a device for managing real memory usage comprising: compressed memory device driver for receiving real memory usage information from said compressed memory hardware controller, said information including a characterization of said real memory usage state: compression management subsystem for monitoring said memory usage and initiating memory allocation and memory recovery in accordance with said memory usage state, said subsystem including mechanism for adjusting memory usage thresholds for controlling memory state changes, whereby control of said real memory usage in said computer system is transparent to said operating system.