Interprocess communications control system

• US 5,437,031 A
• Filed: 02/25/1994
• Issued: 07/25/1995
• Est. Priority Date: 10/10/1990
• Status: Expired due to Term

• Current Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Original Assignee: Fuji Xerox Company Limited (Fujifilm Holdings Corporation)
• Inventors: Kitami, Toshikazu
• Primary Examiner(s): Kriess, Kevin A.
• Assistant Examiner(s): Chaki, Kakali
• Application Number:
  US08/202,674
• Time in Patent Office: 515 Days
• Field of Search: 395/650, 364/228.1, 364/281.6
• US Class Current: 719/312
• CPC Class Codes: G06F 15/161 Computing infrastructure, e.g. computer clusters, blade chassis or hardware partitioning casings, cabinets, racks or drawers for data centers H05K5/00
• CPC Class Codes: G06F 9/544 Buffers; Shared memory; Pipes

Abstract

The improved system for controlling the interprocess communications between a managing process which is a process for managing a plurality of client processes that transmits data to and from the managing process. The system includes an exclusive control means by which only one client process for performing interprocess communications with the managing process is selected from the plurality of client processes, a shared memory which can be referenced by both the managing process and the client processes to perform data exchange between the managing process and each client, and a notifying means which notifies the managing process of data setting in the shared memory by each client.

Claims

1. A data processing system for controlling interprocess communications between a managing process and a plurality of client processes, wherein the managing process is a process for managing the operations of the plurality of client processes wherein each one of the client processes communicates data via a system bus to the managing process, the system comprising:

shared memory means, coupled to the system bus and accessible by the managing process and each of the plurality of client processes, for storing data including a request that is communicated between each of the plurality of client processes and the managing process and a result generated by said managing process in response to the request;

exclusive control means, coupled to the managing process and the plurality of client processes by the system bus, for excluding a second client process of the plurality of client processes from communicating with the managing process using the shared memory means when a first client of the plurality of client processes is communicating with the managing process and for excluding the first client process from communicating with the managing process using the shared memory means when the second client process is communicating with the managing process;

notifying means, coupled to the managing process and the plurality of client processes by the system bus, for notifying the managing process that the first client process has stored the data in the shared memory means to be retrieved by the managing process for processing to generate the result while said exclusive control means excludes the second client process from communicating with the managing process using the shared memory means; and

release means, included in said exclusive control means, for permitting the second client process to communicate with the managing process using the shared memory means after the managing process has retrieved the data that the first client process stored in the shared memory means.

2. The system according to claim 1 wherein each one of the client processes communicates the request and data associated with the request to the managing process, wherein the managing process processes the data in accordance with the request, and wherein the shared memory means comprises:

a client memory portion, accessible by the plurality of client processes and the managing process, for storing data and a corresponding request from each one of the plurality of client processes;

means for effecting a read operation of the client memory portion by the managing process;

a manager memory portion, accessible by the plurality of client processes and the managing process, for storing a value indicating the current status of the client memory portion; and

means for effecting, after the managing process has read the client memory portion, a read operation of the value stored in the manager memory portion by each one of the plurality of client processes.

3. The system according to claim 2 wherein the value indicating the current status of the client memory portion, which is stored in the manager memory portion, indicates that the client memory portion is at least one of available and reserved, wherein available indicates that the client memory portion is capable of being accessed by any one of the plurality of client processes, and reserved indicates that one of the plurality of client processes is currently accessing the client memory portion or that the managing process is currently reading the data and the corresponding request stored in the client memory portion by the one of the plurality of client processes.

4. An apparatus for controlling interprocess communications between a plurality of processes executed by a data processing system including a central processing unit (CPU) and a system bus, wherein the CPU sequentially processes the operations of the plurality of processes, and wherein the operations of a first process of the plurality of processes request communication with a second process of the plurality of processes, the apparatus comprising:

shared memory means, coupled to the system bus, for storing data associated with at least one of a first request of the first process to communicate with the second process and a second request of the second process to communicate with the first process, and for storing a first result generated by said second process in response to the first request and a second result generated by said first process in response to the second request;

exclusive controller means, coupled to the shared memory means via the system bus, for excluding all processes except the second process from accessing the shared memory means after the first process stores data associated with the first request in the shared memory means and for excluding the first process from accessing the shared memory means after the second process stores data associated with the second request in the shared memory means;

event notifying means, coupled to the shared memory means and the exclusive controller means via the system bus, for notifying the second process that the first process has requested communication with the second process and that the data associated with the first request is stored in the shared memory means, permitting the second process to generate the first result while said exclusive controller means excludes the first process from communicating with the second process using the shared memory means, and for notifying the first process that the second process has requested communication with the first process and that the data associated with the second request is stored in the shared memory means, permitting the first process to generate the second result while said exclusive controller means excludes the second process from communicating with the first process using the shared memory means; and

release means, included in the exclusive controller means, for permitting all processes including the second process to access the shared memory after the second process generates the first result and for permitting all processes including the first process to access the shared memory after the first process generates the second result.