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The Wonder that is an Optical Disk

Article Summary: Computers and laptops have proliferated all over the world today due to the phenomenal processing power and functionality they offer. They can do a variety of tasks depending on the software that they run. Due to this, all information available in the world today is increasingly being digitized so that it can be processed by computers.

As a consequence of the rise of optical disks, a need has arisen for removable digital storage devices that can exist as stand-alone units separate from the computer and can be used for taking backups of data as well as transferring it from one device to another.

A variety of such storage devices today exist in the market offering a wide range in terms of price and capacity. These include floppy disks with a puny 1.2 MB capacity, USB drives with a capacity of 1 GB to 8 GB, tape drives that have a capacity of up to 250 GB and portable hard disks whose capacity can go up to 500 GB.

However, the removable storage media that rules the roost today is the optical disk. These disks are really a marvel of engineering and there is hardly any computer or laptop today that does not ship with an optical disk drive. The disks are small but pack a big punch. They are made of a very tough polycarbonate plastic that is very difficult to break or destroy. The disks are circular in shape with a finger hole in the middle.

The disks hold data on their one side only, identified by its shiny surface. The other side, called the label side, is meant for printing text that identifies the disk. The optical disks work with a drive that is built into the computer or laptop. The disk has a tray which slides out to receive the disk. Once the disk is inside the drive, it starts getting spun at a very high rate by a powerful drive motor.

The most crucial part in the drive is the read / write head which can emit and read a laser beam. Once the disk enters the drive, the head moves in position over it and through the laser beam starts etching a pattern of microscopic pits on its data-recording surface. The pits are actually arranged in a single groove that begins from the centre of the disk and goes around in a tight circle, radiating toward the edges. The groove when finished is so long that if unwound, it can stretch for a distance of over 2 km!

In the groove made by the beam, each pit represents one and its absence represents zero, thus making recording of digital data possible. The disk surface is read by the laser beam which is emitted by the head and bounces back to its lens. The operating system then makes sense of the input and turns it into usable data.

Optical disks are of two types – compact discs (CDs) and Digital Versatile Discs (DVDs). The former is the old version that was invented about 25 years ago. It has a capacity of about 700 MB. In the last few years, a more advanced version of the disc, called DVD, has hit the market. This has a whopping 4.6 GB capacity, which is sufficient to hold a full-length Hollywood movie or hundreds of audio files.

The CDs and DVDs both, in turn, come in two versions – Writables (Rs) and Re-writables (RWs). The former can be written over only once. The latter can be written over again and again about a thousand times. The writable CDs and DVDs are much cheaper and ideal for taking one-time archival data backups. The rewritable discs are good for taking backups of everyday work on a regular basis.

The optical disks are very hard to destroy. They are also very cheap and durable, and can be stored for up to ten years without any problem. However, on the flip side, their data-recording surface remains exposed and unshielded from the elements. This can result in data loss. Files on a CD or DVD can become inaccessible if the data-recording surface develops scratches or stains or some kind of thick viscous liquid gets spilt over it.

The smudging or corruption of the disk surface results in the data becoming invisible to the laser and data loss occurs. It is necessary, therefore, for the disc not to lie exposed in the open where it can be damaged. It should either reside in the drive or a protective plastic casing that is easily available in the market.

If you have lost data that you want back desperately, you should try recovering it using commonly available DIY recovery software. If the problem is severe, then you have no option but to approach a professional data-recovery company to get your files extracted.

Article Source: http://www.upublish.info

About the Author:
James Walsh
James Walsh is a freelance writer and copy editor. If you are concerned about data loss and would like more information on Data Recovery see http://www.fields-data-recovery.co.uk