IDL Virtual Machine FAQ

What is the IDL Virtual Machine™ (IDL VM)?
The IDL VM is a freely distributed, cross-platform utility for running compiled IDL code. The IDL VM is designed to provide IDL users with a simple, no-cost method for distributing IDL applications. The IDL VM will allow formal and informal software developers to easily distribute their compiled IDL software code, applets, or entire applications without additional licensing requirements or fees.

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What does the IDL VM cost? Does it cost anything for my end users?
The IDL VM is a free download from the ITT web site. Click here to download the IDL VM.

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On what platforms does the IDL VM run?
The IDL VM is available for all IDL supported platforms, including Windows, Linux, Mac OS X and the Unix operating systems. Because IDL code is platform portable, users can write robust, GUI-driven applications once and deploy them across multiple computing environments. For a grid of the IDL VM platform support, Click here.

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Is a license required to run the IDL VM ?
The IDL VM does not require a license. Once installed, the IDL VM can be run freely with any IDL .sav file compiled with IDL 6.0 or greater. Note that certain optional IDL features, such as extra cost add-on modules may require an extra feature license due to third-party licensing requirements. If such functionality is used in your application a valid license file with the required feature is required.

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Are the GIF/LZW and MPEG features enabled with the IDL VM ?
No, neither GIF nor the MPEG features are available with the IDL VM. The use of the LZW compression algorithm is still protected by patents in areas outside of the US, and data compressed with this algorithm is an integral part of the GIF file format. Until patents for use expire next year the GIF feature is not a part of the IDL VM. The MPEG feature requires a royalty payment for every license that uses the MPEG feature. CREASO currently pays that royalty for all development and runtime licenses sold to customers. Because the IDL VM can be freely downloaded and freely distributed, it is not practical to include the MPEG feature in freely distributed software.

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How can I get the IDL VM ?
The IDL VM is included with all IDL distributions starting with IDL 6.0. When you receive an IDL 6.0 CD, you will also receive the IDL VM. Additionally, you can simply download the IDL VM from the ITT Web site. Click here to download the IDL VM. Once installed, the IDL VM can be run freely with any IDL 6.0 or greater .sav file program.

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How is the IDL VM different from runtime IDL?
As with a normal runtime license, there is no access to the IDL Development Environment or IDL Command Line except in 7-minute demo mode. Similarly, only compiled .sav file programs, not IDL .pro code, can be run using the IDL VM. However, in addition to the freedom from licensing requirements and fees, the IDL VM has a few noteworthy differences compared to runtime IDL:

• The IDL VM displays a splash screen each time it is started. The splash screen must be manually dismissed. Click here to see an image of the splash screen.
• The IDL VM requires .sav files compiled on IDL 6.0 or later.
• While the IDL VM does allow IDL code to embed external objects such as ActiveX controls and Java objects, the IDL VM cannot be used in applications where IDL is called from an external environment. This means that callable IDL applications and applications that use the IDL ActiveX control (IDLDrawX) will not run.
• Use of the IDL EXECUTE function is not allowed. Note that the CALL_PROCEDURE and CALL_FUNCTION routines are allowed and may be valid replacements for many uses of the EXECUTE function. CALL_EXTERNAL and dynamically loadable modules are allowed.
• If your application requires the high resolution global mapping database included as an installation option with IDL, you will need to distribute it to your end users. Only the default low-resolution mapping database is installed with the IDL VM.
• You are prohibited from modifying the IDL VM splash screen or installer.

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Do I need to do anything special to create an application for the IDL VM ?
Nothing beyond what is normally required must be done to create a .sav file compatible with the IDL VM. The IDL VM environment can run any normal .sav file program, as long as it is compiled on IDL 6.0 or later and does not include disabled functionality. See How is the IDL VM different from a normal runtime license?. If you have an IDL .sav file application that you do not want to be accessed in this way, you can enforce your own licensing, such as with a keycode, or you can check for the IDL VM mode in your code on startup to prevent access.

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Can the IDL VM be used to distribute commercial applications?
Yes, the IDL VM can be used to distribute both commercial and non-commercial applications, without licensing requirements or fees. You can simply include the IDL VM distribution code with your .sav file or have the end user download the IDL VM. 

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What other methods of distribution does CREASO offer?
CREASO's existing distribution options including IDL runtime licenses and embedded licensing are still available and may be preferable to those developers who do not wish to have the IDL VM splash screen display when their application is started, or for those who require functionality that is disabled in the IDL VM environment. For more information on the distribution options available please contact us.

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If you have questions about how IDL can increase your productivity and empower your decisions, please contact us.