Embedded Web Server Reference Designs

Web-based device management is quickly becoming an industry standard. It allows separation of the embedded software and the user interface code, use of markups to access and control device internal parameters and on-device embedded data management. The eXtremeWS embedded HTTP server package includes reference designs that demonstrate how the Web server can be used to communicate with remote devices running applications incorporating the eXtremeDB embedded database. Complete source code for the reference applications is available.

Electronic Programming Guide

Digital television technologies, such as set-top boxes and home gateways have sophisticated data management requirements. The Electronic Programming Guide (EPG) manages TV listings, program and channel descriptions, IRD tuning parameters and other related information. The EPG application demonstrates how eXtremeWS can be used to query and control EPG databases. The embedded application communicates with the eXtremeDB in-memory database runtime via in-process CGI, and provides for the initial loading and querying guide data and displaying the guide on the screen.

Embedded Web server and in-memory database in set-top box electronic programming guide

The Web interface for the EPG application contains static and dynamic content. The dynamic content is generated from the eXtremeDB-based EPG database via the in-process CGI functionality provided by eXtremeWS. Static content is processed (compiled) by the eXtremeWS Content Compiler (mkcontent) and linked into the EPG application executable. The EPG application uses a statistically accurate snapshot of programming guide for 14 days of programming on 400 channels. Depending on the platform, the snapshot resides in plain text or compressed files from which the EPG is loaded. In a real-life EPG, the content is received from satellite, cable or terrestrial sources, eliminating the need for a file system.

Automatic Weather Station

This application demonstrates a communication session between the browser and the eXtremeDB database running in the context of eXtremeWS. The automatic weather station (AWS) collects meteological and diagnostic data and communicates this data to the internet browser in form of HTML documents.

Embedded Web server and embedded database in automated weather station

The application simulates the process of collecting temperature, pressure and humidity measurements from sensors, which are then stored in the eXtremeDB database. The METEO database is accessed remotely via an HTML interface that is a mix of static content (such as images) and dynamic content implemented via templates.

Preventive Maintenance Monitoring System

This application demonstrates use of the eXtremeDB embedded database and eXtremeWS embedded HTTP server as the basis for health advisory systems for Pulp and Paper mills. An automatic monitoring and management system for industrial paper machines diagnoses various process and paper machine component conditions and communicates the data to the client, which presents the data analysis in an easy-to-use display. That allows production and maintenance personnel to quickly isolate problems and make immediate adjustments to the process.

The application simulates the process of monitoring with sensors attached to various parts of the paper machine. Accelerometers and thermometers attached to the machine's felt, rollers and bearings collect real-time vibration and temperature data in the database. This data is analyzed in real-time and communicated to the client computer over HTTP. A “Status” page contains the last registered “events” measurements that indicate an alarm, danger or warning state for the controlled equipment. A “Reports” page displays the history for each sensor. Finally, a “Configuration” page allows changes to sensors’ threshold values.

Embedded Web server and embedded database used for preventive maintenance monitoring

The Web interface consists of dynamic content generated at runtime via templates, and static content compiled into the application. The application is very configurable. The amount of RAM and the number of threads used can be established based on available resources.

High Availability Device Management

Process control, telecom and network gear, and other systems with demanding “five-nines” reliability (99.999% up-time) requirements comprise a fast-growing segment of embedded software. Like embedded systems overall, these applications are managing greater volumes of more complex data — creating a need for fast, lightweight databases that can meet their reliability imperative.

The HA Device Management Console application presents a control panel that allows management, control and display of the state of multiple connected devices running eXtremeDB-HA - based applications. Each application reports its current state to the Management Console via a HTTP connection to the eXtremeWS embedded Web server.

Embedded Web server for managing multiple high availability database-enabled devices

The Web interface for the high availability reference application is divided into two parts. The first part of the Web interface catches the output of the eXtremeDB-HA-enabled application running on the controller, and transmits it to the second part of the Web interface. The second part is a HTTP application that aggregates the state data received from the controller’s application and displays this information in the browser. It also includes the HA cluster "control panel" from which the high availability processes can be initiated and terminated.

This application uses in-process CGI and the "template" technology provided by eXtremeWS.