International Business Machines Corporation

Elizabeth Anne Hutchison

Donald W Schmidt

Alan Michael Webb

Susan Patricia Paice

Donna N Dillenberger

Robert F Berry

Rajesh Ramkrishna Bordawekar

Robert Francis Berry

David Francis Bacon

Martin John Trotter

Edmund James Whittaker West

Donna Ngar Ting Dillenberger

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.

Serially, reusable virtual machine

A computer system includes a virtual machine supporting an object-oriented environment, in which programs to run on the virtual machine are formed from classes including methods. Applications run on the virtual machine. After a first such application has run on the virtual machine, a reset is performed on the virtual machine. The reset calls a first method in a class to perform a tidy-up operation which effectively puts the virtual machine back into a clean state. Subsequently a second application can be started on the virtual machine. As part of this start-up, the system calls a second method in the class to perform a reinitialization of the class.

Virtual machine with reset operation

A system includes first and second virtual machines (VM) representing a master and a client respectively. A class file is loading by the first virtual machine into shared memory. The class file includes sharable and non-sharable data, and also references sharable and non-sharable data (including code). When it is desired to load the same class into the second virtual machine, the class is first located within said shared memory. A mirror copy of the class is then formed within private memory in the second virtual machine. Finally the non-sharable data of the class is completed in the private memory. Thereafter, an application in the second virtual machine can utilise the class on the basis of the sharable data in the shared memory of the first virtual machine, and the non-sharable data from the private memory of the second virtual machine.

Class sharing between multiple virtual machines

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Winchester, United Kingdom

Elizabeth Anne Hutchison