Wired on Friday/Danny O'Brien: "Never underestimate the bandwidth of a stationwagon filled with back-up tapes," goes the old internet engineer's saying

In other words, when called upon to install an ultra-fast dedicated cable or satellite uplink to transfer precious digital data, it's always worth considering the alternative of sticking the data onto a large hard drive, pulling it out of the PC, wrapping it in cardboard and sending that by FedEx.

The old devils of the digital world, the software pirates, were working before the internet and knew this adage well. And its future application may return to haunt the beleaguered music industry - perhaps for the last time.

Back in the 1980s, software pirates would run computers off dedicated phone lines, using primitive conferencing software called Bulletin Board Systems (BBSs). Enthusiasts would trade the latest applications, often just for the thrill of it.

They'd use this system to distribute bootleg just as users download software off the net today.

But compared to our modern net, the world of the BBSs was sparsely connected. Instead of a messy intricate web of connectivity that makes up the modern net, each BBS was isolated from the others: a set of hubs with spokes.

Even the hottest new game might take weeks to spread via trading between all the BBSs, run individually from their teenage owners' bedrooms.

So, to spread the best software quickly, the most dedicated pirates would send each other their collections copied onto masses of disks and posted via the regular mail. The small parcel of floppies would take a couple of days to arrive. But with the snail's pace of the network then, it may have taken just as long to transmit the same data by phone.

And with each parcel traded, the collections of illegal software held in each BBS grew. The contents of one parcel would percolate through to the end-users of each new BBS, quickly multiplying that one trade by hundreds and perhaps thousands.

Back then, the authorities tried to disrupt this network by targeting the biggest traders on the BBSs.

In turn, these days, such strategies are being applied against the illicit trading on the file-sharing networks. Hollywood's advocates, the RIAA and MPAA, are currently pursuing users with the largest numbers of illegal copies of movies and MP3s.

It's a smart strategy. Shutting down such "supernodes", together with randomly pulling over the occasional casual trader, can seriously cripple any distribution network. Users become paranoid of strangers' offerings and, therefore, severely reduce any chance for trading. Pirated music fails to move around the network, fails to be copied, fails to thrive.

Mr Clay Shirky, a professor at New York University, has been observing this behaviour on the current P2P networks. He's been noting the decline of open P2P networks, and the rise of file-sharing systems that only work between trusted friends.

Unlike Napster or Kazaa, these programs, such as WASTE or even Microsoft Messenger, do not publish users' files to the world: just to the user's nearest and dearest. They're like the Speakeasies of file-trading: prevalent, widely accepted, but kept secret from the authorities through a tight network of known associates.

For the traders who remember the heady, open days of file-sharing on Napster and its contemporaries, this is thin gruel.

Instead of having the world's music collection, you just have your friends' favourite tracks.

That has to be good news for the music industry in the short term, because what stops trading stops the mass infringement of their copyrighted works.

But trading on the net isn't the only way to exchange illicit content. The equivalent of those parcels of floppies - DVDs and even hard drives being passed from group of friends to groups of friends - is beginning to occur, especially among students.

Hidden offline, such behaviour is hard to trace. It spreads the newest tracks and rare singles, in bulk, across the music industry's biggest target market.

And time is not on the RIAA's side. Recorded music has a relatively short history, and there's a finite number of songs that have been recorded. Prof Shirky estimates there are probably no more than five million tracks in all the albums of the world.

Five million songs stored in MP3 format would take up 15 terabytes - around 15,000 of the gigabytes that hard drives are commonly measured in these days.

That's a lot of storage - but not an inconceivable amount. A modern PC comes with about a hundred gigabytes of storage. A terabyte's worth of storage on its own will set you back about $1,000 (€870) this Christmas. Next Christmas, according to IBM estimates, the cost will drop to close to $400.

By 2008, you'll be able to secure 15 terabytes, enough space to store every piece of music ever recorded, and more, for that same $1,000 - less than the cost of your current PC.

Of course, for this price, the storage you will be buying will be empty. No-one in their right mind would legitimately sell you the entire musical collection of the world for less than a few billion dollars.

But what it does mean is that in a few short years, those pirates will be able to collect - and easily transport - every song in the world, just as those old BBSers could send around the majority of their "warez" in parcels of floppies.

And at that point, the RIAA will no longer just be fighting the trading of individual songs. It'll be fighting the free distribution of its entire crown jewels, contained in a single, easily replicable item: an item that as soon as any of your friends score a copy, you will potentially never have to buy a back-catalogue song again.

An item that is beyond price: and will easily fit in the back of a stationwagon. And that's an inevitability the music industry underestimates at its peril.