Herfried,
If you are looking for a multithreaded solution:
I did not look at your solution however I direct will accept that it will be
as normally from you very fine.
However, what is the reason for multithreading in this. I had long
discussion online and offline with Jon when he was creating his pages about
multithreading about the sense of multithreading, (where to use and where
not).
About this there was not any discussion (in that time he gave me at least
the idea that he thought that it was good to use it everywhere).
Multithreading by disc access will probably only give longer processing
time and an earlier need to renew your discs because of the rumbling you are
creating.
Cor