Before you begin using this Learning Guide, McIDAS must be installed on your workstation and the account you are using must be enabled to run McIDAS. The first time you run McIDAS-X, the $HOME/.mcidasrc configuration file is created. This file stores flags that configure the McIDAS session to your preferences. This file can be edited by you at any time, but the changes will not take effect until the next time you run McIDAS. By changing some of the start-up flags in the $HOME/.mcidasrc file, you can:

• set the number of frames
• allocate additional frame memory
• run commands at startup
• set the text fonts
• set the command and output recall
• set the workstation display
• set the McIDAS Text and Command Window options
• set the McIDAS Image Window options

To start or stop a McIDAS session, follow the steps below:

1. Start McIDAS by entering the following in lowercase from the Unix prompt.

   Type: mcidas

2. Exit McIDAS by typing EXIT on the McIDAS command line. In step 3, you will restart McIDAS and change the display.

   Type: EXIT

3. Start McIDAS again, but this time change the display by editing the flags in the $HOME/.mcidasrc file. Using a Unix editor, vary the number of image frames, the amount of additional frame memory and the number of output lines in each text frame (for more information on the start-up flags, read the documentation within the .mcidasrc configuration file).
   Edit your $HOME/.mcidasrc file, so that your flags match those listed in parentheses below:
   • 6 image frames - each 480 lines by 640 elements (-f 6@480x640)
   • 2 MB memory allocated for creating additional image frames (-e 2m)
   • remember 500 text output lines in each text frame (-oh 500)

   Type: mcidas

4. Exit McIDAS again to learn one final way to change the display.

   Type: EXIT

5. Another way to change the $HOME/.mcidasrc file is to use the command 'mcidas -config' from the Unix prompt.

   Type: mcidas -config

   This displays a configuration window that contains a Graphical User Interface (GUI) with sliders and checkboxes. The sliders and checkboxes are used to select values that override the settings of the corresponding flags in the $HOME/.mcidasrc file. The McIDAS Configuration GUI is designed to make configuration changes easier and less error-prone than other methods. You can make the changes for this session only, or you can save the new settings in the .mcidasrc file.

6. Change the different flags in the configuration GUI and click on the Start button to start the McIDAS session.