TODO:
some issues about the kernel:

How about automatic reading of table of contents when first 
accessing the cdrom disc?

	Eberhard Moenkeberg does this with his sbpcd driver.
	Successive queries to the toc will be satisfied from
	memory.
	Useful for multi track cds only.

Cdrom driver wishlist
	o allow size calculation of *last* track with ioctl
	o support absolut and relative addressing
	o support more sub_q_channel data than position eg
	  International Standard Recording Code or
	  Media Catalog Number
	o support r-w subchannels

	



