Using the Caucus 4.0 interface under 4.1

I. Introduction

Caucus 4.1 has many improvements and bug fixes in both the Caucus user interface (the CML files), and in the Caucus "engine" (the CML interpreter).

While the 4.1 interface is clearly superior to the 4.0 interface, there may be reasons why you would want to continue to run the 4.0 interface with the 4.1 engine.  In an educational setting, for example, it could be confusing to switch interfaces in the middle of a semester.

You could, of course, continue to use Caucus 4.0 and simply not install 4.1.  But the 4.1 engine includes many improvements that would be useful to have immediately.  To give a single example, consider the "pop-up" window that appears when you click on a URL in a response.  In 4.1, you can change the size and shape of that window as you wish; whereas in 4.0, the user is stuck with the initial size of the window.

II. Using 4.0 and 4.1

The best solution is to do both; install Caucus 4.1, but allow the use of both interfaces.  This is easy to accomplish.

For the purpose of these instructions, assume that you have Caucus installed in /home/caucus.  All file names (shown in bold) are relative to that home directory.  Follow the steps below:

  1. Backup the contents of directory SWEB.

  2. Install Caucus 4.1 normally.  This renames your 4.0 entry page (public_html/caucus.html) to a file with the date and time appended, such as public_html/caucus.html.Sep9_1030, and creates a new public_html/caucus.html for 4.1.

    Rename public_html/caucus.html to public_html/caucus41.html; This will be your new 4.1 entry page.

    Rename the "dated" file to public_html/caucus.html; this is your (original) 4.0 entry page.

  3. Rename SWEB/swebd.conf to SWEB/swebd.conf.old
    Rename SWEB/ to SWEB/swebd.conf.  If you had made any custom changes to your original swebd.conf, you may need to make them again in the new file.

  4. Start swebd normally.

  5. Edit the file CML/SP40/Local/macros.i.  To the end of that file, add the text of the file compat.txt.

When you're finished, your users can continue with the 4.0 interface from the same URL (presumably something like  Anyone who wishes to run the 4.1 interface can access it from

(If you have made your own entry page, you can still provide a 4.1 entry page by copying in the relevant links from caucus41.html.)