Dear Jean Louis Lamy,
I have the same problem as you it seems. Did Robert's modifcation's solve the problem?
I have four courses, which are identical but on different days. Next year I will be administrating about 15 different courses, with difference teachers, different class times, but all with the same materials.
It is now possible to back up and duplicate courses. So if I could get all the courses ready before terms begins then it would not be all that much work to duplicate one course 4 or 15 times by backing up and restoring X times.
Unfortunately that is not the case now. I am making the course as I go along. So if I back it up the course which has the latest additions I don't think that I will be able to merge it with the other courses which already have some student grades.
And next year too, and even in theory, there is bound to be the need for an on going system of tweaks, the addition of new resources, and maybe not only by me.
I thought I would be able to use the same course and just add some sort of student identification. I used the "City" (state?) index and changed it to class. I thought that by the end of term I would be able to work out a way of incuding this class entry in the grades table. Then I would only have to update one course page, which all the students could use. And they would have the possibilty of communicating with others outside of their class.
However, since all the class are on different days, this means that a quiz set as preparation for one class, will only be avaialble as revision for another. My time frames are out of sync. Ouch. I am thinking of settling for out of sync quizes this term, but I don't think it is going to work for next year.
My university may be moving in the direction of using Moodle as a framework for online education. There is even one php programmer that may (I hope, please, Ms. Kanayama) be kind enough to help with developments.
In what way might this sort of functionality be implemented?
Tim
Related, (more or less so) posts below.
Groups - this seems to be more concerned with groups within the same course.
http://moodle.org/mod/forum/discuss.php?d=1545
Groups Bug the bug report for the discussion above.
http://moodle.org/bugs/bug.php?op=show&bugid=20
Share resources among courses.
http://moodle.org/mod/forum/discuss.php?d=1115
Using Files and Questions between courses
http://moodle.org/mod/forum/discuss.php?d=1967
How to use same resource twice? (same course)
http://moodle.org/mod/forum/discuss.php?d=2134
central file area
http://moodle.org/mod/forum/discuss.php?d=132
Share uploaded files with different courses
http://moodle.org/mod/forum/discuss.php?d=2912
Form your course from a common place? (YES this!!!)
http://moodle.org/mod/forum/discuss.php?d=2834
Sharing resources (part of the problem)
http://moodle.org/mod/forum/discuss.php?d=1165
How do I duplicate a course? (answered by the next thread)
http://moodle.org/mod/forum/discuss.php?d=3056
A Course duplication feature
http://moodle.org/mod/forum/discuss.php?d=836