NAPSTER and other free music sites promoted, and probably accelerated, more CD sales over the past three years than had been anticipated by the music industry. With the closure of many of these sites, the market has turned and the music industry is suffering reduction in sales for the first time.

So, what next? How about the digital versatile disc (DVD)? Unfortunately, raw DVDs are sold at more than $20 (£14) and burners cost in excess of $500. Why are they so expensive? The differences between a DVD and a CD are so small that the production costs are similar and so DVD blanks should cost a few cents.

Why are the burners so expensive when they, too, are pretty well the same as a CD burner? I can only guess that there is some protection mechanism at work with the media industry vainly hoping to prevent the DVD going the same way as CD. The question is: will they succeed? I think not. The history of the DVD is going to look like the history of the CD - people will find a way.

I recently purchased enough hard drives to create a super-server for the storage of graphical information, multimedia and back-up of a variety of machines. A quick mental sum says that the cost per Gb of hard drive is now less than the cost per Gb of DVD blanks.

So, why would I want to use a DVD, apart from the need to circumvent the lack of networked bandwidth? When I have the option of using a hard drive on a local area network (LAN), available to all my machines and systems, it is by far the most convenient mode.

Now, imagine for a moment the amount of physical space consumed by videos, audio tapes, CDs and DVDs. We, or more likely our children, seem to collect hundreds of video tapes, and are now in the process of repeating this exercise with hugely more expensive DVDs.

This is not all. Purchase, or get a friend to purchase, a DVD in the US and the same DVD in Europe. You will notice the price inflation immediately, and then discover the far richer content on offering from the US. Why are we being short-changed?

Alternatively, if you get a chance to travel in south-east Asia, you can buy for less than £1 some pirated videos of most just about every Hollywood film that you can think of (which all violate copyright).

I think we can assume that the DVD video market will continue to prosper for some time, but set-top boxes and TV sets are arriving with hard drives. Before too long, most of them will be able to install 1,000Gb in their home along with LAN technology that is already available.

Ultimately the success or failure of DVDs and hard drive storage for films, music, software and games will depend on them remaining the cheapest form of information transmission. A DVD in your pocket or in the snail mail, or Frisbee Net as I prefer to call it, is currently the cheapest way of moving bits from A to B. Once we get networked ubiquitous bandwidth, it will be no contest and the hard drives will win.

Professor Peter Cochrane has retired as chief technologist at BT. He has now founded Concept Labs, a company that aims to develop internet-based technologies