What is DVD-RAM?

DVD-RAM is a high-performance, rewritable/recordable, optical disc that enables information to be read, written, erased and re-written again. It acts similar to a floppy disc, where programs can be run from it, data can be stored, or files can be written and deleted. Current DVD-RAM capacity is 4.7GB for a single sided disc and 9.4GB for a double-sided disc. First generation capacity was 2.6GB for a single sided disc and 5.2GB for a double-sided disc. DVD-RAM drives feature backward read compatibility with all CD formats and enhanced durability (100,000 re-write cycles and a 30 + year life span). Double-sided RAM discs can hold more than 14 times that of a standard CD-R. DVD-RAM is the format of choice for such manufacturers as Hitachi, Panasonic and Toshiba.

What are the different types of DVD-RAM?
There are two types of DVD-RAM cartridges: Type 1 is double sided and Type 2 is single sided. Type 2 cartridges can be removed from their cartridges and Type 1 discs are sealed in the cartridge and are not removable. Single sided DVD-RAM discs, when removed from their cartridge, can be read in current DVD-RAM consumer players and computer DVD ROM drives. Double-sided discs are not removable from their cartridges and can only be played back or written in cartridge compatible drives and players.

How does DVD-RAM work?
DVD-RAM is different than DVD-R in that it uses re-writable phase change material rather than the write-once organic dye material that comprises a DVD-R and a CD-R. When writing, a laser heats the phase change material in the disc to about 900-1300F, changing its reflective properties from shiny to dull. If the disc needs to be erased, a laser heats the disc again to about 400F to return the disc to its original shiny state. A laser of lesser power is used to read the written marks. These shiny and dull marks represent data to a computer. They are then interpreted by the computer and then translated into usable information. Second Generation 4.7GB (single sided) and 9.4 (double sided) DVD-RAM achieve their higher capacities by decreasing track width and laser spot size.

What are the differences between DVD-RAM and the other rewritable formats?
First, DVD-RAM media is random access like a hard disk. This enables DVD-RAM to retrieve data faster then the other available formats (current DVD-RAM transfer rate is 22.16Mbps). Secondly, DVD-RAM is more robust than it's competition. It is rated at 100,000 rewrites, while DVD RW and DVD+RW specify approximatly1000 rewrites. DVD-RAM has 9 internal recording surfaces as compared to 3 internal recording surfaces for DVD-RW and DVD+RW. DVD-RAM's metal alloy was created for computer use and therefore affords RAM a far greater number of rewrites. RAM also boasts a sophisticated ECC error correction scheme that makes it ideal for data applications.

What applications is DVD-RAM best suited for?
DVD-RAM's durability and high number of rewrites make it the perfect solution for multifunction jukeboxes providing high capacity, on line storage for document imaging and full motion video. Because of DVD-RAM's speed and error correction technology, these discs are also suited for backup and archiving. DVD-RAM also provides videographers with a solution for storing DV and analog productions instead of hard disc or videotape. By using removable DVD-RAM for mastering and archiving instead of space limited hard drives or poor quality VHS tape, users will achieve the highest quality possible and gain added flexibility. RAM is also well suited for the medical or legal industries. DVD-RAM is currently being utilized in hospitals and radiology labs to store X-rays, CAT scans and other large image files. This provides medical professionals with a reliable, low-cost means of storing test results digitally so they can be easily accessed and shared with others.

What is a DVD-RAM camcorder disc?
DVD-RAM video camcorder disc is a mini sized DVD (8cm) with a recording capacity of 30 minutes. A standard sized DVD-RAM disc is 12 cm and has a recording capacity of 120 minutes using standard quality recording. These mini DVD-RAM discs are used in Hitachi's new DVD-RAM camcorder and can be played back in Hitachi, Panasonic, Toshiba and several other brands of DVD video players.

 

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