American Telephone and Telegraph, Co.

At&t Information Systems Inc.

At&t Bell Laboratories

Bell Telephone Laboratories

American Telephone & Telegraph Co., At&t Bell Laboratories

At&t Laboratories, Limited

Thomas P Bishop

Grover T Surratt

Mark H Davis

James S Peterson

Robert W Fish

David N Horn

David A Schmitt

Lawrence A Welsch

Robert C Hansen

Walter E Tuvell, Jr

Jonas Butvila

David J Fitch

Susan J Picus

A method for allowing a system administrator, application programmer, and/or program user to adjust the processor assignment function in a multiprocessor system. The system administrator controls the assignment function by defining certain system variables and flags. The application programmer can adjust the assignment function by causing allocation parameters to be passed in a system call before execution of the assignment function. To adjust the assignment function, the program user executes a system command that inserts similar allocation parameters into the program object code file stored in a file system on the multiprocessor system. The program executing the assignment function is responsive to the system variables and flags as well as the allocation parameters and performs the assignment function as it has been adjusted on a system, program or user level basis.

Controlled dynamic load balancing for a multiprocessor system

In a multiprocessor system (FIG. 1) wherein each adjunct processor has its own, non-shared, memory (22) the non-shared memory of each adjunct processor (11-12) comprises global memory (42) and local memory (41). All global memory of all adjunct processors is managed by a single process manager (30) of a system-wide host processor (10). Each processor's local memory is managed by its operating system kernel (31). Local memory comprises uncommitted memory (45) not allocated to any process and committed memory (46) allocated to processes. The process manager assigns processes to processors and satisfies their initial memory requirements through global memory allocations. Each kernel satisfies processes' dynamic memory allocation requests from uncommitted memory, and deallocates to uncommitted memory both memory that is dynamically requested to be deallocated and memory of terminating processes. Each processor's kernel and the process manager cooperate to transfer memory between global memory and uncommitted memory to keep the amount of uncommitted memory within a predetermined range.

Multiprocessor memory management system with the flexible features of a

There is a disclosed a multi-processing arrangement in which processes running on one processor may utilize processes, called stub processes, running on other processors. One problem that occurs with respect to such a system is that signals, which indicate the occurrence of external asynchronous events, must be processed in a specified order if the system is to work properly. Disclosed is a system for insuring the proper processing of such signals by requiring all such signals to be routed from a receiving process on a adjunct processor to the main user process on the originating processor. Also disclosed is an arrangement for insuring that signals are not lost and that duplicate signals are not processed.

Handling of notification of asynchronous events by user and stub

Processors (101) of a multiprocessor system (FIG. 1) communicate across bus (150) via a low-latency packet protocol featuring per-logical channel input queues (143) and output queues (144), different per-processor priorities for sending data packets (FIG. 10) and data packet-acknowledging 'quick' messages (FIG. 11), and separate buffers (923; 918) for receiving data packets and 'quick' messages, respectively. Transmitted data packets afflicted by error, receive buffer overflow, and input queue-full conditions are discarded by the receiving processor and are retransmitted by the sending processor.

Inter-processor communication protocol

In a multiprocessor system, a program's execution that is controlled by controlling an extended process that spans a plurality of processors. The extended process comprises an user process on one processor for executing object code of the program and stub processes each on an individual one of said remaining processors for accessing system resources required for execution of the program. Each stub process gives the extended process access to the resources associated with the processor executing the stub process. Further, a stub process is unique to one particular extended process. Each stub process is interconnected to the user process by an individual virtual communication channel. The virtual communication channels are identified in each process by a port table that is unique to an individual process. When the user process accesses a local file, the access is through a user file table, a system file table, and an inode table. When the user process accesses a remote file, the access is through the port table, over the virtual channel identified from port table to a stub process, and then through the stub process' user file table, system file table, and inode table.

Extended process for a multiprocessor system

A multiprocessor system automatically responding to a request for executing a new program to establish an extended process that spans a plurality of processors each having resources required for the execution of the new program. Initially, the extended process comprises an user process that is requesting the execution of the new program. Stub processes are created as required to gain access to the object code file of the new program, to allocate a processor to execute the new program, and to initialize the allocated processor for execution for the new program.

Virtual execution of programs on a multiprocessor system

A is a duel processor system (100) with duplicated memory (114,124) has two modes (10,11) of operation: a converged mode (10) in which one of the two processors (101,102) is active and executing all system tasks while the other processor is inactive; and a diverged mode (11) in which both processors are active and independently executing different tasks. The system automatically changes modes in response to requests such as manual and program control and certain system fault conditions. In diverged mode, the system may be in either of two states of operation (1 and 2). In one state (1) one processor (101) is designated a primary processor, and in the other state (2) the other processor (102) is designated the primary processor. In the converged mode the system may be in either of four states of operaton (3-6). In two of these states (3,4) one processor is active while the other processor is standing by ready to take up execution of tasks from the point where the one processor stoped execution. In the other two of these states (5,6) one processor is active while the other processor is out of service and cannot take up task execution without being initialized. The system 100 makes transitions between the various states in response to requests. Except for transitions of an active processor to an out-of-service condition, the state transitions are transparent to tasks other than fault recovery programs and, upon a fault condition, the faulted program.

Reconfigurable dual processor system

In a multiprocessor system (FIG. 1), memory (22) of each adjunct processor (11-12) comprises global memory (42) and local memory (41). All global memory is managed by a process manager (30) of host processor (10). Each processor's local memory is managed by its operating system kernel (31). Local memory comprises uncommitted memory (45) not allocated to any process and committed memory (46) allocated to processes. The process manager assigns processes to processors and satisfies their initial memory requirements through global memory allocations. Each kernel satisfies processes' dynamic memory allocation requests from uncommitted memory, and deallocated to uncommitted memory both memory that is dynamically requested to be deallocated and memory of terminating processes. Each processor's kernel and the process manager cooperate to transfer memory between global memory and uncommitted memory to keep the amount of uncommitted memory within a predetermined range.

Multiprocessor memory management method

An arrangement for introducing modifications in the program of a program-controlled system. Each time a modified version of a selected program function is stored in the system, it is tagged with a function sequence number; meanwhile, the original version of the program function is retained in the system. Each time a program process is initiated, it is tagged with a process sequence number. The two types of sequence numbers are assigned from a common source. Whenever the selected program function is called by a program process, a comparison is made between the process sequence number and the function sequence number. If the comparison indicates that the process was initiated before the modification was stored in the system, the original version of the selected program function is executed; otherwise, the modified version is executed. Thus, the original version or the modified version is used consistently throughout the active life of a process.

Growing community of inventors

Aurora, IL, United States of America

Thomas P Bishop