For Computing homework i have to answer 32 questions on Operating Systems. Mostly the answers are in the book, but i cant find these few - or on the net, prolly not searching for the right stuff..

1) Briefly explain how I/O ‘channels’ function – what is a ‘handler’ and a ‘driver’?
2) Use a diagram to explain ‘double buffering’
3) Distinguish between ‘spooling’ and ‘polling’, give examples
4) What is ‘re-entrant’ code? When would it be used?
5) Describe the concept of a ‘thread’
6) Distinguish between high and low level scheduling

Anyone know what these are/do/how to explain them?

Thanks all

EDIT: wasnt really sure which forum to put this in - thinking about it, probably better in Operating System bit....