Thanks, RBS,had a look at that site, I'm sure it makes a lot of sense to you, thanks for making it clear, [or clearer] to me, especially as I thought it was a physical thing, not a term!. see, you're still assuming that I am getting used to IT technology, I am, but slowly, wait 'til you get old!!
Seriously though, I'm sorry if I irritate you, I assure you it's not intentional., there are so many things to learn.
Thanks Page2564 as well, some more gobble-de-gook explained!
Maurice.