Abstract: In a virtual machine environment, a method and apparatus for the use of multiple heaps to retain persistent data and transient data wherein the multiple heaps enables a single virtual machine to be easily resettable, thus avoiding the need to terminate and start a new Virtual Machine as well as enabling a single virtual machine to retain data and objects across multiple applications, thus avoiding the computing resource overhead of relinking, reloading, reverifying, and recompiling classes. The memory hierarchy includes a System Heap, a Middleware Heap and a Transient Heap. The use of three heaps enables garbage collection to be selectively targeted to one heap at a time in between applications, thus avoiding this overhead during the life of an application.

Abstract: A computer system provides an object-based virtual machine environment for running successive applications. The computer system includes storage, at least a portion of which is logically divided into two or more heaps in which objects can be stored. A first heap is reset between successive applications, and a second heap persists from one application to the next. A card table is provided which comprises multiple cards, each corresponding to a region of said storage. Each card in the card table is set to null when the first heap is reset between successive applications. A card is marked whenever an object in its corresponding storage region is created or updated. It is then possible to detect potential references from the second heap to the first heap at reset by scanning the cards in the card table corresponding to the second heap, and detecting any cards which have been marked. The system further identifies any objects on the first heap which have a finalization method.

Abstract: A computer system provides an object-based environment. The computer system includes storage. A contiguous linear portion of the storage is logically divided into first and second heaps located at opposite ends of the linear portion of storage. Any gap between the two heaps represents an unallocated region of storage. The system permits references from objects on the first heap to objects on the second heap and vice versa. A garbage collector operates across both heaps to remove objects that are no longer live. Means are provided for expanding the first and second heaps into the unallocated region. The first heap is expanded according to a first expansion policy, and the second heap is expanded according to a second expansion policy.

Abstract: A computer system provides an object-based environment and includes storage. At least a portion of the storage is logically divided into two or more heaps in which objects can be stored. Each heap is subdivided into slices of memory. The system includes a two-level lookup structure for determining whether a given storage address corresponds to a particular heap. The lookup substructure involves a first level having one or more lookup substructures, each corresponding to a unit of memory representing a predetermined number of slices. The substructure indicates for each of these slices the particular heap, if any, that the slice belongs to. The two-level lookup structure further involves a second level for determining for a given memory address the first level lookup substructure that includes the slice containing that address.

Abstract: Extended business transactions are processed in a client-server system in a manner which allows processing initiated by a client to be interrupted before the transaction is complete and later resumed by the same or another client from the point of interruption. This is achieved by storing state information indicative of the progress of the transaction in a repository in association with an end-user identifier. When the end-user communicates his identifier via a client to the server for a second time, processing of the transaction can be resumed on the basis of the stored state.

Abstract: A computer system provides an object-based environment. The computer system includes storage. A contiguous linear portion of the storage is logically divided into first and second heaps located at opposite ends of the linear portion of storage. Any gap between the two heaps represents an unallocated region of storage. The system permits references from objects on the first heap to objects on the second heap and vice versa. A garbage collector operates across both heaps to remove objects that are no longer live. Means are provided for expanding the first and second heaps into the unallocated region. The first heap is expanded according to a first expansion policy, and the second heap is expanded according to a second expansion policy.

Abstract: A computer system provides an object-based virtual machine environment for running successive applications. The computer system includes storage, at least a portion of which is logically divided into two or more heaps in which objects can be stored. A first heap is reset between successive applications, and a second heap persists from one application to the next. A card table is provided which comprises multiple cards, each corresponding to a region of said storage. Each card in the card table is set to null when the first heap is reset between successive applications. A card is marked whenever an object in its corresponding storage region is created or updated. It is then possible to detect potential references from the second heap to the first heap at reset by scanning the cards in the card table corresponding to the second heap, and detecting any cards which have been marked.

Abstract: A computer system provides an object-based environment and includes storage. At least a portion of the storage is logically divided into two or more heaps in which objects can be stored. Each heap is subdivided into slices of memory. The system includes a two-level lookup structure for determining whether a given storage address corresponds to a particular heap. The lookup substructure involves a first level having one or more lookup substructures, each corresponding to a unit of memory representing a predetermined number of slices. The substructure indicates for each of these slices the particular heap, if any, that the slice belongs to. The two-level lookup structure further involves a second level for determining for a given memory address the first level lookup substructure that includes the slice containing that address.