1   Workbench System Requirements

The AstroGrid Workbench will run on any operating system (OS) on which Java is available, this includes Windows XP, Linux and Mac OS X. You will need the appropriate Java Run Time Environment (JRE) for your OS, version 1.4.2 or higher (the recommended version is JRE 1.5 which is also referred to as Java 2 Platform Standard Edition version 5.0). The minimum system RAM recommended is 512M.

If you are unfamiliar with Java or need help installing it then please read the following sections for more information.

2   What is Java

The Java programming language was developed in the early 90s by Sun Microsystems, predominantly for writing applications. Although it is very similiar to programming languages such as C and C++, it has one major advantage over them (and most other) programming languages in that it is platform independent - the same program file can be executed on multiple operating systems.

The platform independence of Java has made it an extremely popular programming language for distributing applications across the internet. Many of these applications come in the form of Java Applets, which are programs that can be included in web pages in the same way that images are. Applications may also be downloaded as a single file in the Java Archive format (identified by the .jar extension to the file name) and are launched independently of the web browser. The applications provided in this format are typically much more powerful than those provided as Java Applets.

The Java Run Time Environment or JRE is a software package that enables a particular operating system to execute Java applications, be they Applets or .jar files. The JRE includes the Java Virtual Machine (or JVM) which is the program that interprets the Java code and executes it on your computer. You will need a JRE installed on your computer to launch the AstroGrid Workbench. Please read Installing Java for information on how to check whether you have a JRE installed and what to do in the event that you don't or that you do not have the correct version of the JRE.

3   Installing Java

Sun Microsystems provide a web page from which one can check whether a JRE is installed and if one is, the version of the JRE installed; click here to visit this page. If the web page indicates that a JRE is installed, make a note of the version number and compare it to the Workbench System Requirements. If the web page indicated that a JRE was not installed or, that the installed version is not high enough to launch the Workbench then please keep reading to find out how to rectify this.

The method by which the JRE is installed is different for each OS. Please read the section below which is relevant to your operating system. Please note that currently there is no version of the Java Web Start application (read `What is Java Web Start`_ for more information) for 64 bit processors. If you are intending to launch the Workbench or any helper applications using Java Web Start then you must install the 32 bit JRE.

4   What is Java Web Start

Java Web Start is an extension to the JRE, enabling standalone Java applications to be started from the internet by clicking a link on a web page. These web links point to Java Network Launching Protocol files (recognised by the .jnlp file extension) which provide information about the application such as the location of the Java Archive file. When the Java Web Start application reads the .jnlp it will verify whether it has downloaded the application before. If the application hasn't been downloaded before, it will do so and store it in its local cache directory. If the application has been downloaded previously, it will verify whether a new version of the application exists and if it does it will download it and replace the old version in its local cache.

The Java Web Start program is normally installed with the JRE automatically and if you followed the instructions for your operating system under Installing Java, then clicking on a Web Start link in your browser should automatically download and launch the application. If you are using the Mozilla web browser and it does not appear to be correctly configured, please read Configuring Mozilla to Launch Java Web Start for information on how to rectify this.

Depending upon the configuration of your computer, the local Java Web Start cache will probably be located in your home directory. The AstroGrid Workbench can take upwards of 20 Mb in disk space and applications such as SPLAT can take upwards of 100 Mb of disk space. If you have a disk quota or have limited disk space it is possible that downloading the AstroGrid Workbench or any of the helper applications will take you over your allocated disk space. It is therefore advisable to change the location of your cache directory to a more suitable directory. Please read Changing the Location of Your Local Java Web Start Cache to find out how to do this.

MIME Type: application/x-java-jnlp-file
Description: Java Web Start
Extension: jnlp

4.3   Java Web Start Security and Digital Signatures

When Java applications are launched using Java Web Start they do so in a very secure environment in which they cannot access any files on your computer or any network that you are connected to. The AstroGrid Workbench requires network access to function and when it is first launched a window similar to the one below will appear (the design/layout of the window will be dependent upon your OS).

The purpose of this window is effectively to confirm that the user trusts the downloaded application and is happy for it to access the network and local files. In this situation the application is a known one and it would be safe for the user to click the "Always trust these certificates" tick box (to prevent the window appearing on the next launch of the Workbench) and then click the "Trust" button to continue. All Java Web Start applications need to be "trusted" in this way so you may see a similar window for some of the helper applications (e.g. Aladin and SPLAT) if you decide to use them. The user should remain vigilant for unknown applications requesting permission to access the network and local files.

5   Installing and Launching the Workbench

The AstroGrid Workbench can be installed and launched in two different ways. The easiest method is to launch it using Java Web Start (read What is Java Web Start for more information) by clicking the "Click Here to Launch AstroGrid" on the Getting Started web page. You can also download the application and install it locally, which is recommended for continued use. To install the application, first click here to visit the download page and download and save the Workbench installer file (it will have filename similar to "workbench-2007.1.1-installer.jar"). The installation file can be executed at the command-line/terminal by typing:

java -jar workbench-2007.1.1-installer.jar

Follow the instructions in the window that appears to install the AstroGrid Workbench. After installing and launching the AstroGrid Workbench, please read the Science User documentation for information on how to use it.