I’m currently doing a couple of maths courses with the Open University (OU), for which we get booklets containing the course material by post. In recent years, the OU have made the material available on-line as well, for current students. This is very handy if you need to access things while away from home. However, one of my current courses doesn’t have the material on-line at the moment.

What’s going on? The course has been presented for a number of years (the original copyright is 1993), and so there were originally no PDF files: everything was printed from film. This being a maths course, the original source was TeX-based. So you’d expect that the OU could just re-TeX the source using pdfTeX and all would be okay. That is, if they still had the source!

The moral: TeX may be stable, but you still need the source files.