These are available in either Read only or read/write devices
CD ROM – A CDROM can store up to 700MB of information on a disc and so are the medium of choice for most users. Manufacturers now supply most software either on CDROM or DVDROM due to the high capacity available.
CD R/W – These devices are the same as a CDROM but can also record up to 700MB of information on writable CDROMS for later use. Blank discs are available in either CDR (Write once) or CD R/W ( write many times). These come in a number of write speeds from 1-52 speed or higher
DVD ROM- A DVDROM can store up to 15.9GB of information on one disk although most disks are usually either 4.7GB or 8.5GB. These devices are commonly used for distribution of DVD films or large programs such as Encyclopedias.
DVDR/W – These devices are the same as a DVDROM but can also record up to 8.5GB of information on writable CDROMS for later use. Blank discs are available in either DVDR (Write once) or DVD R/W ( write many times). Blank dvd media comes in either 4.7GB or 8.5GB and in a variety of recording speeds from 1 – 18 and either dvd- or dvd+ formats.
DVD – RAM – These have a similar storage capacity to DVDR but are R/W and are often used in home dvd recorders as they are considered to have higher reliability than DVD.
New Optical Storage Formats
These are the current leading edge and as such are quite expensive but decreasing in price very quickly.
BLU-RAY – These are aimed mainly at the high definition television/movie market as they can store either 25GB or 50GB of data. Blue-ray writers currently start at circa £350 and media at £7 each. Further development in blu-ray has resulted in tests of 100GB and 250GB discs. Pioneer announced a 400GB disc in 2008. A 1TB blue-ray disc may be with us as soon as 2013.
JVC has also developed a 3 layer technology disc which will play on a standard dvd player and also a blu-ray player. Infinity have produced some discs using this technology comprising a single blu-ray layer(25GB) and 2 x 9GB standard dvd layers on the same side of the disc. If this is commercially succesful it will bring the gap between dvd and blue-ray.
HD DVD – These are a competing format with blue ray storing 15GB or 30GB of data. Prices of writers and media are similar to blue ray. This format has now been discontinued by the manufacturer Toshiba.
ULTRA HD BLU-RAY – Developed by Sony current storage limit of 100GB released in 2016. Require a new Ultra HD blu-ray player as exsiting players are not campatible.
Other formats currently with limited availability or in development are.
DMD – 22 to 32GB of storage. Now probably a dead format as D Data inc who were developing it now seem to have disappeared as there are currently no signs of any commercial products.
VMD – 20 to 50GB or storage. The original company behind VMD de-registered as a company early 2007. In October 2008, it was reported that the technology behind HD-VMD had been revived by three apparently related companies – Royal Digital Media, Anthem Digital and DreamStream, to produce a new 100GB optical disc. Players and some content was released on the format such as the children’s tv program series "lazytown" but no discs or players appear to be produced anymore.
TAPESTRY MEDIA – Initial disc sizes are 300GB with a theoretical limit of 1.6TB. This was due end of 2007 but to date has not been released.
HVD – These are still in the development stage but should offer a theoretical maximum storage of 3.9TB or between 4,600–11,900 hours of video in the new MPEG4-ASP format or 26.5 years of stereo audio !. Initial prices of the recorders are estimated to be £7500+ and the blank discs £60 to £90 each. Although these were demonstrated at the end of 2007 to date no one has commercially produced a HVD disc. There are rumours that they are being used by some usa television stations for archival purposes but there is no firm evidence of this. The HDV forum also looks to be pretty quiet as the last posting was in April 2008. This is located at http://www.hvd-forum.org/. Forum has now been removed
PH-DVD – Initial disc sizes are reportedly 100GB. Looks to now be a dead format as no players or discs look to have very been released.
Protein-coated disc – Theoretical limit of 50TB. This is a standard dvd coated in dna modified protein. Production discs were due late 2007 or early 2008 but no further development news has been forthcoming.
Two-Photon 3-D Optical – Still in development. Theoretical disc size of 1TB. Development seems to have stopped and no players or discs every seem to have been released.
FVD, or Forward Versatile Disc, is an offshoot of DVD developed in Taiwan jointly by the Advanced Optical Storage Research Alliance (AOSRA) and the Industrial Technology Research Institute (ITRI) as a less expensive alternative for high-definition content. The disc is similar in structure to a DVD, in that pit length is the same and a red laser is used to read it, but the track width has been shortened slightly to allow the disc to have 5.4GB of storage per layer as opposed to 4.7GB for a standard DVD. The specification allows for up to three layers for total of 15GB in storage. The register reported that the FVD was due to released to mass market way back in 2005 although ther is not much evidence of this. http://www.theregister.co.uk/2005/11/30/fvd_volume_production/. Development of this format now looks to have been discontinued.
CH DVD China Blue High-Definition (CBHD)- This format offers similar storage to HD-DVD the format that it is based on. In early March 2009, Warner Bros announced that they would be supporting the CBHD format, launching with titles including the Harry Potter series and Blood Diamond, with discs selling for between 50 and 70 yuan (roughly $7.25 to $10.15). According to an August 2009 television story by TV-Tokyo, CBHD was outselling rival Blu-ray by a margin of 3 to 1 in China.In September 2009, Universal Studios and National Geographic announced their support for the format. Additionally adding support for the format are Paramount (US), Celestial (HK/CN) and BBC/Discovery (UK/US). Format now looks to have been discontinued.
VCDHD (Versatile Compact Disc High Density) or DVHD (Disc Versatile High Density) – This is developed by Phillips and has the same capacity as a DVD and can be played on existing dvd players. Capacities of 15GB are muted for later dvd players using a blue laser. See article on http://www.engadget.com/2006/03/29/new-optical-disc-standard-joins-the-fray/ for a more detail. Now looks to have been discontinued.
Ultra Density Optical (UDO) – capacity of 30gb, generation 2 capacity of 60gb. Originally developed by Sony. ASTI currently sells and supports UDO technologies sold under the Plasmon brand. As of 2017 UDO drives and discs are still available although Mistsubishi has been the sole manufacturer of UDO media since 2008.
Stacked Volumetric Optical Disc (or SVOD)–developed by Hitachi/Maxell storage of circa 1TB. Development now seems to have stopped.
5D DVD – Currently being developed in Australia with a theoretical limit of 100TB. Uses 3 lasers to read/write the disc instead of the current 1. See link below for more information. Development now seems to have stopped.
‘5 Dimensional’ glass – Developed at the university of Southampton. This uses nanostructures stored in glass on a 1 inch disc, so a standard sized disc has a theretical storage limit of 360GB and a life of 13.8 Billion years! Due to high cost of the high precision femtosecond ultrafast lasers a commercial release may be many years away. There are a lot of demonstration videos on the format on youtube. (search for 5D storage)
PDD – Developed by Sony 128GB limit discontinued 2007
MODS – Developed at Imperial College London 1TB limit. Development status unknown
For the sake of completeness other formats that have been used are GD-ROM (dreamcast console), UMD(sony psp) and Nintendo optical disc and WII optical disc for the respective consoles.
Footnote- Although there are many future formats in development BLU-RAY has such a large marketplace and with blue-ray development ongoing a lot of the other formats may never gain a foothold.
These are available in either Read only or read/write devices
|There is a large number of these devices. The common ones are USB pen drives or Flash type cards. These are now very inexpensive and offer good storage capacity. USB pen drives are now available with 512GB+ of storage capacity. The flash cards are commonly used in mobile phones and digital cameras although there are several different types of these which are incompatible with each other. Solid state hard disc drives are also available for laptop and desktop computers although these are very expensive at the moment. A 240GB "SSD" will set you back circa £100 and a 1TB would set you back circa £400.|