Bull Hn Information Systems, Inc.

Mary E Tovell

William E Woods

Dennis R Flynn

Richard A Lemay

Thomas S Hirsch

Richard S Bianchi

Marcia T Fogelgren

Marek Grynberg

An emulator executes on a second data processing system as a second system user level process including a first system user level program, a first system executive program, and first system user and executive tasks. An emulator level is interposed between the second system user level process and a kernel level and contains pseudo device drivers. Each pseudo device driver corresponds to a first system input/output device. The kernel level includes kernel processes, each kernel process corresponding to a pseudo device driver. The second system hardware platform includes a plurality of second system input/output devices, wherein each second system input output device corresponds to a kernel process. Each combination of a pseudo device driver, a corresponding kernel process and a corresponding second system input/output device executes in a second system process and emulates the operations of a corresponding first system input/output task and the corresponding first system input/output device. The pseudo device drivers are constructed of a plurality of pseudo device queues, a return queue and a queue manager.

Executing programs of a first system on a second system

A memory translation mechanism and method executing in a second system to perform first system memory operations for first system executive and user tasks executing on the second system which includes a second system memory organized as a plurality of memory segments, wherein first memory segments are designated to correspond to system memory areas and second memory segments are designated to correspond to user memory areas, and wherein each memory segment corresponds to a combination of a type of first system task and a type of a first system memory area. An interpreter maps by reading an identification of the type of the task corresponding to the first system virtual address from the task type memory and the area type value from the first system virtual address and determining a memory segment corresponding to the type of the first system task and the type of first system area referenced by the first system virtual address. The interpreter maps the identified segment to a memory pool identifier wherein each memory pool identifier corresponds to a task. The second system includes a plurality of pseudo device drivers corresponding to first system input/output devices. Each pseudo device driver includes a segment mapping mechanism which includes a segment pool for storing entries relating memory pool identifiers and providing a corresponding base address identifying the location of the corresponding memory segment in the second system memory.

Emulating the memory functions of a first system on a second system

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Newton, MA, United States of America

Mary E Tovell