Welcome

Welcome to CoreDX DDS, a high-performance implementation of the
OMG Data Distribution Service (DDS) standard. The CoreDX DDS Publish-Subscribe
messaging infrastructure provides high-throughput, low-latency data
communications.

This Quick Start will guide you through the basic installation of CoreDX DDS,
including installation and compiling and running an example Java application. You will
learn how easy it is to integrate CoreDX DDS into an application. This Quick Start Guide
is tailored for Java applications, and the examples differ slightly for C applications.

Installation

First things first: get CoreDX DDS onto your development
system! Here's what you need to do:

1. Once you have obtained CoreDX DDS from Twin Oaks
   Computing (or from the Eval CD), unpack the appropriate
   distribution for your machine somewhere on your system. We'll
   refer to this directory throughout this guide as COREDX_TOP.
   For example, on a UNIX system this command will extract the
   distribution into the current directory:

   gunzip -c coredx-3.0-Linux_2.6_i686-Release.tar.gz | tar xvf -

   CoreDX DDS is available for multiple platform architectures,
   and multiple platform architectures of CoreDX DDS can be
   installed in the same top level (COREDX_TOP) directory. The
   directory structure under COREDX_TOP will look like:

   alt="CoreDX DDS Directory Structure">

2. If you are using an evaluation copy of CoreDX
   DDS, follow the instructions you received when you
   downloaded the software to obtain an evaluation license.
   Otherwise, use the purchased license provided by Twin Oaks
   Computing. Once you have the license, put this file
   somewhere on your system. We'll refer to
   the full path name to this file throughout this guide as LICENSE_FILE.

Building an Application

The next step is to integrate CoreDX DDS into an application! We've
provided a sample data type and applications with the distribution
(located in COREDX_TOP/examples). You can use these examples or create your own
while going though the following steps. Our example Makefiles were built for
gcc (UNIX systems) and Visual Studio cl.exe (Windows systems).

1. Create the Data Definition Language (DDL) file for the data type(s)
   you will use for communications. The CoreDX DDS DDL syntax is very
   similar to the OMG IDL syntax for describing data types. Here is the
   "hello world" example provided with the distribution:

   hello.ddl

   struct StringMsg { string msg; };

2. Tell the CoreDX DDS DDL compiler where your evaluation
   license is located. You can copy the license file into
   the directory where you will run the compiler; or, set the
   following environment variable, using the full path to your
   license file. (This assumes a bash style shell):

   % export TWINOAKS_LICENSE_FILE=LICENSE_FILE

3. Compile the DDL to generate the type specific code using
   the CoreDX DDS DDL compiler. The DDL compiler is a
   host tool, and is located in the host subdirectory.

   Actually, there may be more than one DDL compiler in the installation,
   if you have multiple platform versions of CoreDX DDS installed.
   In this case, choose the appropriate compiler for your architecture.
   Assuming we are using a Linux distribution and the name of the DDL
   file is hello.ddl:

   % COREDX_TOP/host/bin/Linux_26_x86_gcc43_coredx_ddl -f ../hello_c/hello.ddl -l java 

   The compilation will generate the following files in a "gen" subdirectory
   (files names are based on the DDL type name):

   • StringMsg.java
   • StringMsgTypeSupport.java
   • StringMsgDataReader.java
   • StringMsgDataWriter.java

4. Create code to publish data of this data type. Our sample
   Hello World publisher is located in
   COREDX_TOP/examples/hello_csharp/hello_pub.cc.

5. Create code to subscribe to data of this data type. Our sample
   Hello World subscriber is located in
   COREDX_TOP/examples/hello_csharp/hello_sub.cc.

6. Compile your application(s). Our Hello World example creates
   two applications, one for the publisher and one for the subscriber.
   This is not necessary, and is completely dependent on your application
   architecture. Your application will require the objects from the generated
   type support code above, as well as your publisher and/or subscriber code.

   CoreDX DDS will require the following paths and libraries when
   compiling your application:

   • Class Path: -cp classes -cp ${COREDX_TOP}/target/java/coredx_dds.jar

   We've provided a compile.sh (UNIX) and compile.bat (Windows) for compiling
   our example. You can use these as a reference for compiling your application.
   Our scripts require three environment variables:

   • COREDX_TOP
   • COREDX_HOST
   • COREDX_TARGET

   The COREDX_TOP is a path name to the location of your CoreDX DDS
   distribution(s). COREDX_HOST and COREDX_TARGET are the platform
   architectures you are compiling on and compiling for (these can be the same).
   These values can be set manually, or determined by running the
   script: COREDX_TOP/scripts/cdxenv.sh or cdxenv.bat.

   Our scripts will run the DDL compiler to generate the type specific
   code as well as compile the applications. To compile the Hello World
   sample application using our scripts you will need the Java JDK
   (specifically, javac) in your path. Then, simply run 'compile.sh' for UNIX
   or 'compile.bat' for Windows in the appropriate directory.

   This will compile several class files, including the HelloPub and HelloSub classes.

Running a Test Application

You've written some code, generated some code, and compiled
it all. Now for seeing it all work! You will need at least one environment
variable to run:

TWINOAKS_LICENSE_FILE = The full path to your evaluation license

On Windows

You will also need the same COREDX environment variables needed for the compile above:

1. COREDX_TOP
2. COREDX_HOST
3. COREDX_TARGET

Run your application(s). We provide scripts to run the example hello_pub and hello_sub applications.

For UNIX:

run_sub.sh

run_pub.sh

For Windows:

run_sub.bat

run_pub.bat

Congratulations! You have now built and run two applications
that are communicating using CoreDX DDS.

Figure 1 shows a picture of what you have built:

Figure 1: Example Components

You can run multiple Publishers and multiple Subscribers to
immediately see the dynamic nature of the DDS network infrastructure.
These Publishers and Subscribers can be run on the same host
or on multiple hosts across a network.

A few notes about the Transport

The default CoreDX DDS transport conforms to the Real-Time Publish-Subscribe (RTPS)
Wire Protocol standard. This transport does not require a stand-alone
transport daemon, and does not require configuration of any operating
system services.

The CoreDX DDS RTPS transport can be configured using the following
environment variables. These items can also be configured through
the use of Quality of Service (QoS) policies. Refer to the CoreDX
DDS Programmer Guide for more information and additional options.

A few notes about License Files

CoreDX DDS uses development and run-time licenses. A development license
is required for using the CoreDX DDS DDL compiler (coredx_ddl).

A run-time license is required for making CoreDX DDS library function
calls. Both licenses are contained in a license file provided by Twin
Oaks Computing.

Here is an example license file containing evaluation licenses for both
development and run-time:

#======================================================================
# CoreDX DDS Evaluation License file
#
# Created:   by Twin Oaks Computing, Inc.
# Contains: 30 day evaluation development licenses, evaluation run-time licenses
#
#======================================================================
 
LICENSE PRODUCT=coredx_ddl BUILD=Evaluation EXP=31-Aug-2008
CUSTOMER=Company_X SIG=
4ccad329d5a10b93460ff3b249cea6733f6bd408d22b5fe9cb2a2c69b0d575e69a5d
c14b436b90c2ed6b516930452b862133cf7d2a9301d46ce99865f78c998311adeb99
3f68da82b74f1583511edab1d0de61dbe065f38955dd6596f0b564639fed231b1af8
61b6df122040173804e0e61b0dba37d6913cfc66d319217df099

LICENSE PRODUCT=coredx_c BUILD=Evaluation EXP=31-Aug-2008
CUSTOMER=Company_X SIG=
30b3c5d6f941c5ff5e46384eb1b74bd1809dfbd53ca11fa4d7442054bb260846588
c4bd7a5c7f7a986a12905b22dbdc428a67ee2d2c806ed5f1a14c35deb03e3a8ce6a
2fda8fdb7e5728c3103f239b51aca3b3911901e2e959fe020a21b7b7cb72dee8ca8
da8fa73cc69d3572738259025c212815aef2f94111580f51583e437
        

This evaluation license file contains two LICENSE lines. The first is
the development license for the CoreDX DDS DDL compiler. The second is
the run-time license for the CoreDX DDS library. All evaluation licenses
have expiration dates. In the example file above, the license expire
on Aug 31, 2008.

The CoreDX DDS software requires a license environment variable be set:
TWINOAKS_LICENSE_FILE. This environment variable can contain either:

• The fully qualified name of the license file, or
• The entire LICENSE line from the license file contained in angle brackets: < >

For development (to run the coredx_ddl compiler), you must set the
TWINOAKS_LICENSE_FILE environment variable to the license file.

For run-time, you can use either method listed above. If you have
access to the license file from your run-time environment, this is the
simplest way to use the license. Simply set a TWINOAKS_LICENSE_FILE
environment variable to the license file.

If you do not have access to the license file at run-time,
you can set the TWINOAKS_LICENSE_FILE environment variable to the LICENSE
line. For the run-time license in the above example license file,
set your TWINOAKS_LICENSE_FILE like:

% export TWINOAKS_LICENSE_FILE="<LICENSE PRODUCT=coredx_c BUILD=Evaluation
EXP=31-Aug-2008 CUSTOMER=Company_X SIG=30b3c5d6f941c5ff5e46384eb1b74bd1
809dfbd53ca11fa4d7442054bb260846588c4bd7a5c7f7a986a12905b22dbdc428a67ee
2d2c806ed5f1a14c35deb03e3a8ce6a2fda8fdb7e5728c3103f239b51aca3b3911901e2
e959fe020a21b7b7cb72dee8ca8da8fa73cc69d3572738259025c212815aef2f9411158
0f51583e437>"

A Few Notes About DDS Keys

DDS provides a facility for user defined data types to identify one or more fields
as a "key". By specifying a key, the published data will be categorized into
instances. An instance refers to a collection of samples, where each sample
has an identical key value. For example, consider a data type that has a field 'x'
identified as the key and the type of 'x' is a long integer. All samples with x=5,
belong to the same instance. A DataWriter can publish several samples with x=5
and they all refer to the same instance. The DDS middleware can be configured, via the
History QoS, to keep all samples of an instance, or only a certain number of samples.

You specify the key for your data type by inserting some
additional information into the DDL file. This provides an indication to the
DDL compiler that it should generate additional code to correctly handle the key
information.

For example:

#ifdef DDS_IDL
#define DDS_KEY __dds_key
#else
#define DDS_KEY
#endif
 
struct StringMsg
{
  DDS_KEY long    id;
          string msg;
};
        

This example adds a key called 'id'. The #ifdef block at the beginning simply
removes the "DDS_KEY" symbol if the file is not being processed by the CoreDX
DDS DDL compiler. This ensures that ddl files maintain compatibility with
standard IDL syntax.

Several fields can be marked with the DDS_KEY modifier. In this case, all 'key'
fields are used together as the key for the data type.

A few notes about the DDL Compiler (coredx_ddl)

The coredx_ddl compiler handles a few command line arguments. The following briefly
describes the command line options and arguments. For more information and additional
options, please refer to the CoreDX DDS Programmer Guide.

Changes from Previous Release

For current release notes, visit the Twin Oaks Computing website at:


http://www.twinoakscomputing.com/documents/RELEASE_NOTES.txt

Contact Information

Have a question?

Don't hesitate to contact us by any means convenient for you:

Web Site:http://www.twinoakscomputing.com

Support:

Email: support@twinoakscomputing.com

Phone: 720.733.7906

Online Forum: CoreDX DDS Forum

Primary Sales Office:

Email: sales@twinoakscomputing.com

Phone: 720.733.7906

EMEA Sales Office:

Email: emea.sales@twinoakscomputing.com

Phone:+33 (0)9 62 23 72 20