What is the Difference Between DVD-RAM and DVD-ROM?

Digital Versatile Disc Random Access Memory (DVD RAM) and Digital Versatile Disc Read-Only Memory (DVD ROM) are two types of data storage technology which involve the encoding of data via laser onto a disc. Depending on the application, one may be more suitable than the other. In general, DVD RAM is used to store data, while DVD ROMs are used for movies and supplemented music presentations.

A DVD ROM is designed to be read only. This means that once the data has been encoded, the disc is in a fixed state and cannot be changed. This makes it highly suitable for storing data which would not need to be overwritten or changed, as is the case with a film. In addition, it is readable in almost any type of machine, from a computer to a conventional DVD player. This means that the disc is more widely accessible for users.

The data on a DVD RAM can be rewritten numerous times over the period of its life, and for this reason the discs are favored for data storage. Typically, it is housed in a protective cartridge, due to the higher cost of the disc. Some systems have difficulty reading these discs, but support for them is almost universal on computer systems made after 2000.

A DVD RAM uses a type of technology known as phase change on the physical disc to store the data. The disc has a special layer of material made from a mixture of metals which is highly responsive to heat. When the laser makes contact with it, one temperature will cause the alloy to be crystalline, while a higher temperature will turn it amorphous. Thus, it is possible to record binary data onto the disc for playback, and to erase the data and write over it later.

If cared for properly, a DVD RAM is estimated to be able to last up to 30 years, and through at least 1,000 rewrites. The write speed for a DVD RAM is fairly high, and very accurate thanks to high quality disc defect management. They are frequently used in camcorders and digital cameras to house a high volume of data which can be transferred to another medium before the disc is overwritten.

If a computer user wants a highly flexible backup system which is capable of being rewritten numerous times, a DVD RAM is an excellent choice. If storing data which can remain static, a DVD ROM is a less expensive and more suitable option.