Iowa State University Research Foundation, Inc.

Newmonics Inc.

Kelvin D Nilsen

William P Schmidt

Steven J Lee

Simanta Mitra

The invention is a real-time programming method (RTPM) for use in writing application programs to be executed by virtual machines and a method practiced by a real-time virtual machine (RTVM) while executing an application program written in accordance with a real-time programming method. The invention also includes a method for translating an RTPM programming language into a second programming language, the RTPM programming language being an extended version of the second programming language. The RTPM programming language includes real-time code expressions for specifying real-time execution requirements. The method of translating the real-time code expressions is such that the execution of a second-language translation of a RTPM-language application program complies with the real-time execution requirements on a best-effort basis. The RTPM utilizes a configure method and a negotiate method. The invocation of the configure method in an application program results in the quantification of the needs for one or more resources during execution of the application program by a virtual machine. The invocation of the negotiate method in an application program causes a negotiation to occur between the application program and the virtual machine concerning the allocation of one or more resources to the application program, the resources including CPU time, total memory, and memory allocation rate.

Real-time programming method

The object space manager circuit is a device used in computer memory systems for determining the address of the first word of an object, given the address of any other word in the same object. It consists of a first-object-word encoding circuit, a memory circuit, and a first-object-word decoding circuit. The encoding circuit utilizes a hierarchical coding system to generate codes that relate the address of a first object word to any other object word. This particular coding system results in codes that are the same for particular ranges of object word addresses. The codes are stored in the memory circuit which permits the entry of a code at each address of a specified range of memory addresses to be accomplished simultaneously. The decoding circuit utilizes an input object-word address to retrieve the associated codes from the memory and then translates these codes into the address of the first object word.

Object space manager circuit for obtaining addresses of object headers

The invention is a method for use in executing portable virtual machine computer programs under real-time constraints. The invention includes a method for implementing a single abstract virtual machine execution stack with multiple independent stacks in order to improve the efficiency of distinguishing memory pointers from non-pointers. Further, the invention includes a method for rewriting certain of the virtual machine instructions into a new instruction set that more efficiently manipulates the multiple stacks. Additionally, using the multiple-stack technique to identify pointers on the run-time stack, the invention includes a method for performing efficient defragmenting real-time garbage collection using a mostly stationary technique. The invention also includes a method for efficiently mixing a combination of byte-code, native, and JIT-translated methods in the implementation of a particular task, where byte-code methods are represented in the instruction set of the virtual machine, native methods are written in a language like C and represented by native machine code, and JIT-translated methods result from automatic translation of byte-code methods into the native machine code of the host machine. Also included in the invention is a method to implement a real-time task dispatcher that supports arbitrary numbers of real-time task priorities given an underlying real-time operating system that supports at least three task priority levels. Finally, the invention includes a method to analyze and preconfigure virtual memory programs so that they can be stored in ROM memory prior to program.

Method for efficient soft real-time execution of portable byte code

The invention is a random access memory assembly which is a key component of an object space manager which in turn is a key circuit in a garbage-collecting control unit for a computer system. An object space manager provides the means for deriving pointers to headers of objects from pointers to internal data of objects. The object space manager comprises an encoder that generates an object locator code for each memory cell in which an object is resident, a random access memory assembly for storing the object locator codes for all memory cells in which objects are resident, and an object locator which identifies the memory cell containing the header of an object by means of the object locator code for any memory cell occupied by the object.

Random access memory assembly

The garbage-collecting memory module (GCMM) functions much like traditional memory in a computer system, thereby permitting the invention to be utilized with a wide variety of computers. It differs from traditional memory in that it automatically cleanses itself of garbage while functioning as traditional memory without causing excessive delays in the execution of application programs by an associated computer. The GCMM can be designed to interface with a computer system via a traditional memory bus and to communicate with the central processing unit (CPU) of the computer using standard communication protocols. The GCMM is comprised of a memory, a means for communicating with the CPU, and a garbage-collecting control unit. The garbage-collecting control unit gives top priority to satisfying the computer's requests for memory services. The collection of garbage takes place during the intervals between memory service requests. Garbage collection is accomplished by copying live objects that are stored in one region of memory to a second region thereby leaving dead objects behind in the first region. When the copying process has been completed, the dead objects are disposed of, and the garbage-collecting process continues with the copying of live objects in the second region back to the first. An up-to-date list of live objects is maintained by the CPU and forwarded to the GCMM at the start of each garbage-collection cycle.

Object space manager method and circuit

The CPU-controlled garbage-collecting memory module (CPU-C GCMM) is essentially an intelligent memory that connects to a central processing unit (CPU) and performs the routine and repetitive tasks associated with a spectrum of garbage-collecting techniques under the direction and control of the CPU. The CPU-C GCMM performs its garbage-collecting tasks as background tasks to be performed when the CPU-C GCMM is not burdened with the ordinary fetch and store operations necessitated by the application programs being run on the CPU. The CPU-C GCMM can be structured in a variety of ways. One species which embodies the essence of the invention includes a memory and a memory controller which provides the means for reading data from and writing data to the memory. The memory controller receives fetch requests directly from the CPU and returns the requested data immediately even though the data may be incorrect in certain instances. A microcontroller which exercises overall control over the component parts of the CPU-C GCMM together with a fetch monitor work together to repair any incorrect data deliveries to the CPU by the memory controller. A communication-channels unit provides the means of communication between the CPU and the microcontroller for handling all interactions between the CPU and the CPU-C GCMM except fetch requests. An object space manager unit provides a means for rapidly identifying the header of an object given a pointer to the interior of an object.

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Ames, IA, United States of America

Kelvin D Nilsen