Cascade DataHub™

Version 4.0

Jan 08, 2003

A memory resident real-time database that acts as a hub, providing fast and efficient concentration and distribution of data for QNX and Linux applications.

Note

With version 4.0, Cogent software now includes source-code compatibility among the QNX 4, QNX 6 and Linux operating systems, a reorganized and expanded API, and other improvements. Version 4.0 of Cogent's tools will not interoperate with version 3 or older. This documentation has been edited and reorganized to reflect those changes. For documentation of Cogent software version 3.x, please contact Cogent Real-Time Systems, Inc.


Go to the Cogent Web Site.

Copyright © 1995-2002 by Cogent Real-Time Systems, Inc.

Table of Contents
1. Introduction
1.1. What is the Cascade DataHub?
1.2. A note about the Cascade DataHub API
1.3. System Requirements
1.4. Download and Installation
1.4.1. QNX 4
1.4.2. QNX 6
1.4.3. Linux
1.5. Where can I get help?
2. Using the Cascade DataHub
2.1. Running the Cascade DataHub
2.1.1. Configuration
2.1.2. Testing the Cascade DataHub installation
2.2. Using the Cascade DataHub Viewer
2.2.1. Console Mode
2.2.2. QNX Photon Mode
2.2.3. X Windows Mode
2.3. Features
2.3.1. Exceptions and Echoes
2.3.2. Asynchronous Messages
2.3.3. Network Access in QNX
2.3.4. Domain Independence
2.3.5. Confidence Factors
2.3.6. Security and Point Locking
2.3.7. Unlimited Point Count
2.3.8. Cascade DataHub performance
3. Data Transmission
3.1. Synchronous data transmission
3.2. Asynchronous data transmission
3.3. Cascade DataHub data transmission
I. Utilities
datahub -- starts the Cascade DataHub.
dhview -- a console-based viewer for the Cascade DataHub.
phdhview -- a Photon-based viewer for the Cascade DataHub.
xdhview -- an X Windows-based viewer for the Cascade DataHub.
readpt -- reads a point from the Cascade DataHub.
waiter -- registers for exceptions with a Cascade DataHub and displays values as updates are received.
writept -- writes a point to the Cascade DataHub.
Index
Colophon
List of Tables
2-1. Memory Usage
List of Figures
2-1. The Cascade DataHub Viewer in Console Mode
2-2. The Cascade DataHub Viewer for QNX Photon
2-3. The Cascade DataHub Viewer for X Windows
2-4. Exceptions and Echoes
2-5. Asynchronous Messages
3-1. Synchronous data transmission
3-2. Asynchronous data transmission
3-3. Cascade DataHub Data Transmission
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Colophon   Introduction
Copyright 1995-2002 by Cogent Real-Time Systems, Inc.