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Last Updated: Friday, 6 October 2006, 15:41 GMT 16:41 UK
Future of the hard drive 'secure'
Chris Long
By Chris Long
BBC Click reporter

With all the developments in memory technology you could be forgiven for thinking that the lowly hard drive is dead.

Hard drive close-up, Eyewire
The terabyte hard drive uses perpendicular recording

But although the hard drive is 50 this year, we have seen yet more growth in the technologies around it. The one terabyte drive is more or less here, we have perpendicular recording and they are getting smaller all the time.

Without Daniel Bernoulli we would not have a name for the effect that we rely on to make the hard disk work.

The Bernoulli Effect is what happens when a wing moves through the air - it floats. Just like an aeroplane's wing, the read head of a hard disk floats across the top of the disk.

"As the disk spins this lifts the head up off the media," explained Ian Keene of hard drive manufacturers WD.

He added: "Many people think the head is actually touching the media, but the distance between the head and the media is in the distance of 100 angstroms; to give you some idea of what an angstrom is, a human hair is about one million angstroms."

Perpendicular storage

Liam Rainford of hard drive makers Seagate, believes that the operation of a disk drive is quite unique in computer terms.

"The disks spin at up to 15,000 revs per minute. The data is stored on the disk in magnetic form, and each code on the disk has got magnetic poles, north and south.

"In the traditional sense this was stored in longitudinal form, which meant that north and south were side by side on the surface of the disk.

The capabilities and bandwidth of SATA are significantly greater than those of USB or Firewire
Liam Rainford, Seagate

"New breakthroughs have brought us the ability to store that data perpendicularly in the surface of the disk, meaning we have a north and south pole embedded into the surface of the disk."

This new "down through the disk" rather than "along it", perpendicular recording technique has changed the game when it comes to the amount of storage we are going to get from a hard disk; look out for a one terabyte hard disk early next year.

However, perpendicular recording is not the only new technology about. We now have a new and much faster way to connect the disk to the computer - serial ATA (SATA).

It has been around for internal drives for a while but now external SATA, or eSATA, is the hot new way to connect external drives, and will compete with USB and Firewire.

"The capabilities and bandwidth of SATA are significantly greater than those of USB or Firewire," said Liam Rainford.

"I still anticipate that the three are going to co-exist happily together for the foreseeable future."

This is going to be a relief to all the people with USB and Firewire drives, and there are an awful lot of them out there. In the UK alone there is an astonishing amount of storage being sold.

Safety concerns

"Every day we sell one million gigabytes of storage, that is 1,000 terabytes - the equivalent to 1.6 billion digital photographs," said Katie Cohen of computer retailer PC World.

A hammer, Eyewire
Smashing drives is the most efficient method of destroying data

Just in case you do not know, 1,000 terabytes is a petabyte. Get used to those two words because we are going to be hearing an awful lot of them in the next couple of years.

With all this storage, and the opportunity to never throw any of your data away, the issue of security grows.

It is surprisingly difficult to clean your data off a hard disk, and while there are lots of software out there on the web that claims to overwrite all your sensitive data, a lot of people in the business say there is only one way of making the hard disk unreadable - smash it to pieces!

With all this storage comes the responsibility of looking after the data, and that does not simply mean backing up, it means defragmenting, or defragging to the cognoscenti.

"Effectively, what you're doing when you're defragging is you're putting all your data blocks next to each other," said Mac Motraghi of Hitachi.

"[This means] your hard disk doesn't have to go to several different locations trying to find bits of the same file. It improves the ability of your hard disk to supply the right data to the operating system."

Twenty or so years ago a 40 megabyte drive was about the biggest capacity you could buy.

Today we have smaller, faster 500 gigabyte drives. Next year it will be a terabyte - that is a lot of storage, and it is all down to Bernoulli, apparently.

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