System and method for a delta page protocol for caching, replication, and client/server networking

• US 7,383,315 B2
• Filed: 08/02/2001
• Issued: 06/03/2008
• Est. Priority Date: 08/02/2001
• Status: Active Grant

• Current Assignee: National Instruments Corporation (Emerson Electric Company)
• Original Assignee: National Instruments Corporation (Emerson Electric Company)
• Inventors: Fox, Dudley Wayne Jr., Pierce, David Mark
• Primary Examiner(s): Burgess; Glenton B.
• Assistant Examiner(s): BATES, KEVIN T
• Application Number:
  US09/920,893
• Publication Number:
  US 20030055605A1
• Time in Patent Office: 2,497 Days
• Field of Search: 709/214, 709/215, 709/216, 702/187, 702/179, 702/182, 702/188, 707/2, 707/3, 707/20.1, 707/204
• US Class Current: 709/217
• CPC Class Codes: H04L 43/026 using flow identification
• CPC Class Codes: H04L 43/045 for graphical visualisation of monitoring data
• CPC Class Codes: H04L 67/1095 Replication or mirroring of data, e.g. scheduling or transport for data synchronisation between network nodes
• CPC Class Codes: H04L 67/12 specially adapted for proprietary or special-purpose networking environments, e.g. medical networks, sensor networks, networks in vehicles or remote metering networks
• CPC Class Codes: H04L 69/329 in the application layer [OSI layer 7]

Abstract

A method and system for a delta page protocol for caching, replication, and client/server networking. Measurement data may be received by a logger application on a first computer, and written to shared memory sections in a modular fashion, including creating one or more header records to indicate a changed status. Each shared memory section may be independently accessible by a trender application executing in a second computer. In response to a query from the trender, the first computer may send a single message, a delta page. The header record may be used to determine the changed status of data sections. A single write operation may store the data values in a memory of the second computer. The trender may then read the first plurality of data values. The trender may present the retrieved data or requested data on a display. The logging and trending may be performed substantially concurrently.

Claims

1. A method of logging and trending real time measurement data, the method comprising:

a logger application executing on a first computer system receiving a measurement stream comprising a plurality of real time measurement data values, wherein the plurality of real time measurement data values are acquired from a physical system by a measurement device;

the logger application writing portions of the plurality of real time measurement data values to respective shared memory sections of a memory in the first computer system in a modular fashion;

wherein each of the portions of the plurality of real time measurement data values in each of the respective shared memory sections is independently accessible by a trender application executing in a second computer system;

initiating the trender application on the second computer system;

the trender application generating a query request for a first portion of the plurality of real time measurement data values;

the first computer system sending a single message to the second computer system, wherein the single message comprises the first portion of the plurality of real time measurement data values, wherein the first portion comprises two or more of the real time measurement data values;

the trender application receiving the single message comprising the first portion of the plurality of real time measurement data values;

the trender application displaying the first portion of the plurality of real time measurement data values.

2. The method of claim 1, wherein each of the portions of the plurality of real time measurement data values in each of the respective shared

memory sections is independently accessible by a trender application executing in a second computer system using a single network message.

3. The method of claim 1, wherein each of the portions of the plurality of real time measurement data values in each of the respective shared memory sections independently and accurately represents a subset of the measurement stream.

4. The method of claim 1, wherein the single message is a delta page.

5. The method of claim 1, wherein the logger application receives the measurement stream and writes the portions of the plurality of real time measurement data values to respective shared memory sections of the memory at a first data rate;

wherein the trender application generates the query request for the first portion of the plurality of real time measurement data values at a second data rate, wherein the second data rate is less than the first data rate.

6. The method of claim 5,

wherein the first computer system sending a single message to the second computer system comprises:

a first observer software program executing on the first computer system querying the memory for a most recent portion of data at the second data rate; and

the first observer software program sending the most recent portion of data to the second computer system at the second data rate after said querying the memory;

wherein the trender application receiving the single message comprises;

a second observer software program on the second computer system receiving the most recent portion of data at the second data rate from the first observer software program; and

the second observer software program writing the most recent portion of data to a memory location.

7. The method of claim 6, wherein the memory location is a database.

8. The method of claim 1, wherein the trender application is operable to partially replicate the plurality of real time measurement data values comprising the measurement stream.

9. The method of claim 1, wherein the logger application writing portions of the plurality of real time measurement data values to respective shared memory sections of a memory in the first computer system in a modular fashion comprises:

creating a header record comprising a series of bits, wherein the bits in the header record indicate a changed status of the respective shared memory sections;

the logger application writing the header record in the shared memory.