Abstract: A computer system having a main memory for storing data in a compressed format and a processor cache for storing decompressed data, a method for converting the data of said main memory from compressed to uncompressed state, comprising the steps of reducing used portions of said main memory to a target value; disabling a compressor used for compressing the uncompressed data; decompressing said compressed data of said main memory; moving said decompressed data to physical addresses equal to real addresses; and releasing the memory occupied by a compressed memory director and data structures used in the above steps.

Abstract: A method is provided for manipulating a compressed translation table in a memory expansion technology system. The method comprises swapping contents of an output buffer with contents of a compression buffer, disabling compression for compression translation table entries corresponding to the content swapped to the compression buffer, and packaging entries of a compression translation table corresponding to the contents swapped to the compression buffer, wherein packaged compression translation table entries are accessible to a computer system for addressing the contents swapped to the compression buffer.

Abstract: 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 the compressed main memory, there is provided a system and method for managing real memory usage comprising: a compressed memory device driver for receiving real memory usage information from the compressed memory hardware controller, the information including a characterization of the real memory usage state: and, a compression management subsystem for monitoring the memory usage and initiating memory allocation and memory recovery in accordance with the memory usage state, the subsystem including mechanism for adjusting memory usage thresholds for controlling memory state changes.

Abstract: A system and method for managing a memory storage device including a physical memory having free space for storing content maintained in compressed form and organized as pages. The system includes a control device for managing performance of input and output operations of compressed content to and from the memory storage device, with output operations including a memory pageout operations for recovering free memory storage space. The control device maintains an amount of free storage space readily available for recovery to above a threshold amount so as to enable subsequent pageout operations to be performed. A novel data construct is provided that includes locations of pages which may be immediately cleared from the physical memory for a subsequent pageout operation, the control device performing a flush operation by accessing the data construct and expediently deleting one or more pages identified in the list as available for deletion.

Abstract: A computer system having a main memory for storing data in a compressed format and a processor cache for storing decompressed data, a method for converting the data of said main memory from compressed to uncompressed state, comprising the steps of reducing used portions of said main memory to a target value; disabling a compressor used for compressing the uncompressed data; decompressing said compressed data of said main memory; moving said decompressed data to physical addresses equal to real addresses; and releasing the memory occupied by a compressed memory director and data structures used in steps a. to d.

Abstract: In a system with hardware main memory compression, the method of this invention monitors the physical memory utilization and if physical memory is near exhaustion it forces memory to be paged out, thus freeing up real memory pages. These pages are then zeroed, thus they are highly compressible and therefore reduce the physical memory utilization. Pages that have been forced out due to high physical memory utilization are not made available for allocation. In systems where operating system changes are permitted, this invention dynamically controls the minimum size of the free page pool and zeros pages upon freeing. When the physical memory utilization falls below a critical threshold the mechanism reduces the minimum size of the free pool to allow further allocation. In systems where operating system changes are not possible, pages are allocated by a module (e.g. Device driver) and then zeroed.

Abstract: A method is provided for manipulating a compressed translation table in a memory expansion technology system. The method comprises swapping contents of an output buffer with contents of a compression buffer, disabling compression for compression translation table entries corresponding to the content swapped to the compression buffer, and packaging entries of a compression translation table corresponding to the contents swapped to the compression buffer, wherein packaged compression translation table entries are accessible to a computer system for addressing the contents swapped to the compression buffer.

Abstract: 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 the compressed main memory, there is provided a system and method for managing real memory usage comprising: a compressed memory device driver for receiving real memory usage information from the compressed memory hardware controller, the information including a characterization of the real memory usage state: and, a compression management subsystem for monitoring the memory usage and initiating memory allocation and memory recovery in accordance with the memory usage state, the subsystem including mechanism for adjusting memory usage thresholds for controlling memory state changes.

Abstract: An improved method, system, and a computer program storage device for management of compressed main memory allocation and utilization. The present invention has features which advantageously avoid system abends or inefficient operation that would otherwise result. We identify 3 types of addresses associated with a page: a virtual address, a real address, and a physical address. The OS is responsible for converting virtual addresses to real addresses, and the memory controller is responsible for converting real addresses to the physical addresses where the compressed data are actually stored. We assume that the memory controller has the capability to store a page either compressed, or uncompressed. Depending on the characteristics of the controller, this may be done either on a per page basis via an indicator bit that is settable by the OS, or on a range of real addresses.