CD and DVD Formats

On a daily basis I’m still asked about the different forms of blank disc available on the market and the differences between them.For this reason I thought this week we would look back at all the commonly available disc based media formats and the differences between them; from the humble CD to the more recent BluRay and HD-DVD.

CD-R – Whilst the CD format has been available since the early 1980’s, the specification for the writable version (CD-R) was published further down the line, in 1988.Whilst available in a number of different variants, the most commonly available is the 700mb version with a write speed of typically 52x (52 times the speed of the original CD-R standard).Whilst they don’t offer the storage capacity of newer alternatives such as DVD, they are still ideal for storing smaller amounts of data, for example a music album.CD-RW is a rewritable variant of the write once CD-R disc.

DVD-R – This format is typically capable of holding up to 4.7Gb (4700mb) of data and offers write speeds surpassing the CD-R standard.This makes the DVD-R an ideal choice for storing larger files, or indeed movies.There are DVD-RW (Rewritable) discs available along with a Dual Layer version which uses a second layer on the same disc which almost doubles the capacity to 8.5Gb

DVD+R – A rival format to the DVD-R, the DVD+R is technically very similar, but there are a number of subtle differences that distinguish the two.Whilst most end users wouldn’t notice between the two, the existence of the two formats means that if buying a DVD disc, you need to ensure that you pick the correct format unless you have a drive which supports both.As with DVD-R, this format is also available in DVD+RW and DVD+RW Dual Layer.

DVD-RAM – A competing format to the rewritable formats DVD-RW and DVD+RW, the latest revision of the DVD-RAM standard offers a maximum storage capacity of 9.7Gb.Considered extremely reliable, along with being designed for constant re-recording (a DVD-RAM disc can be rewritten 100,000 times compared to just 1,000 times for a DVD-RW or +RW disc), this format is ideal for frequent data backup.Its popularity has been hindered by the fact it’s approximately five times more expensive than a –RW or +RW disc.

HD DVD – This format was developed by a consortium of companies with the intention that it would be the successor of the conventional DVD.Exactly the same physical size as a standard DVD disc, this format allowed a maximum storage capacity of 15Gb per layer with a Dual Layer version to double this space to 30Gb.Recordable discs for this format are still expensive, costing over a fiver each.Unfortunately Toshiba who were the main driving force behind HD DVD, announced a couple of days ago that they would no longer be developing or manufacturing players and recorders for this format, meaning that it has essentially lost out to its main competitor, BluRay.

BluRay Disc – So named because of the blue laser that is used to read the bottom of the disc, the BluRay format has been developed by a number of companies that form the BluRay Disc Association.Technically a superior format to HD DVD, BluRay discs can store 25Gb per layer meaning that a Dual Layered disc will hold a massive 50Gb of data making them ideal for high definition movies.The success of this format is in no small part down to the Playstation 3 being equipped with a reader as standard.

There are also options regarding the type of surface on the top of the disc.A technology known as Lightscribe will allow you to literally etch a design in to the top of the disc using a laser built in to a compatible writer.Alternatively other discs have a white, paper style surface which allows the printing of directly on to the disc using a compatible printer.Next week we’ll look at these technologies in more detail.


About the Author - Chris Holgate works for Refresh Cartridges who supply a wide range of printer cartridges at the UK’s lowest prices.