Environment > Distributing IDL Applications > Virtual Machine Applications > Starting a Virtual Machine Application

# Starting a Virtual Machine Application

Installations of IDL that have access to a development license can create compiled binary versions of IDL applications; these compiled versions are stored in files with the extension `.sav`. Many applications stored in `.sav` files can be executed by the IDL Virtual Machine.

If you use the MAKE_RT procedure to create a runtime distribution, specifying a SAVE file for your application, application launch scripts for your application are created automatically. (You may need to modify the launch scripts.) If you do not use MAKE_RT, you can still create application launch scripts based on generic scripts included in the IDL distribution.

Alternately, you can provide instructions for your users detailing how to run a `.sav` file in the IDL Virtual Machine. The process depends on your operating system:

- Windows
- UNIX
- Mac OS X

## Windows

Windows users have several options to start a Virtual Machine application:

To run an application stored in a `.sav` file:

1. Double-click on the `.sav` file icon in the Windows Explorer. If a development license is present, the application will run in a licensed copy of IDL. If no license is present, the IDL Virtual Machine window will open.
2. Click anywhere in the window to run the application in the IDL Virtual Machine.

To open a `.sav` file from within the IDL Virtual Machine:

1. Launch the IDL Virtual Machine and display the IDL Virtual Machine window by selecting Start > Programs > IDL x.x > IDL Virtual Machine.
2. Click anywhere in the IDL Virtual Machine window to close the window and display the file selection menu.
3. Locate and select the `.sav` file, and double-click or click Open to run it.

To run a `.sav` file from the command line prompt:

1. Select Run from the Start menu, and enter `cmd`.
2. Change directory (`cd`) to the `IDL_DIR\bin\bin.platform` directory.
3. Enter the following at the command line prompt:

    idlrt -vm=<path><filename>

where `<path>` is the path to the `.sav` file, and `<filename>` is the name of the `.sav` file.

## UNIX

UNIX users must launch the IDL Virtual Machine from the UNIX command line.

To run a `.sav` file in the IDL Virtual Machine:

1. Enter the following at the UNIX command line:

    idl -vm=<path><filename>

where `<path>` is the complete path to the `.sav` file and `<filename>` is the name of the `.sav` file. The IDL Virtual Machine window is displayed.

2. Click anywhere in the IDL Virtual Machine window to close the window and run the `.sav` file.

To launch the IDL Virtual Machine and use the file selection menu to locate the `.sav` file to run:

1. Enter the following at the UNIX command line:

    idl -vm

The IDL Virtual Machine window is displayed.

2. Click anywhere in the IDL Virtual Machine window to close the window and display the file selection menu.
3. Locate and select the `.sav` file and click OK.

## Mac OS X

Macintosh users have several options to start a Virtual Machine application:

To open a `.sav` file from the IDL Virtual Machine:

1. Double-click the IDL x.x Virtual Machine icon to display the IDL Virtual Machine window.
2. Click anywhere in the IDL Virtual Machine window to close the window and display the file selection menu.
3. Locate and select the `.sav` file and click OK.

To run the IDL Virtual Machine from the UNIX command line, see the UNIX steps.

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