As a DVD-RAM is referred to one of the three rewritable DVD formats, which should be distinguished from the other two by its better being rewritten and data security. The DVD-RAM is used in both computers as well as camcorders and hard disk recorders.

History and distribution

Originally there were only pure play DVDs like DVD-Video, DVD-Audio and DVD -ROM. Besides, this should initially be only for the computer area and a rewritable DVD format, the DVD-RAM. The " RAM " stands for "Random Access Memory ". Meanwhile, the DVD-RAM is also very successfully used in other fields, such as video.

The DVD-RAM is indeed the oldest rewritable DVD format, but it is less common than the other two rewritable DVD versions DVD-RW and DVD RW. The reason is that the members of the DVD Forum industry association they had indeed approved in 1996 together, but for various market interests, the DVD formats DVD -RW and DVD RW additionally introduced. Both competition formats are also based on the phase - change technology, but they have some savings, which are charged to a good Rewritability and data security. The two DVD versions DVD -RW and DVD RW will be briefly referred to as DVD ± RW.

The first devices for DVD-RAM, in 1997 on the market. Since 2002, the DVD-RAM gained an increasing market importance, because it has established itself in the DVD - VCR and DVD camcorders because of their advantages in the ease of being rewritten and easier handling compared to DVD ± RW as standard. About the wider dissemination of DVD-RAM media prices have dropped, so that it is now interesting for use in the consumer space for backups of computer data. The greater market importance of DVD-RAM in the computer area is also recognized in that the former self-confessed advocate of DVD -RW, the manufacturer Pioneer, now also offers DVD burner that can handle DVD-RAM.

For computers, no exact information is about the actual distribution of the DVD-RAM in the application possible because since 2004, the DVD burner that can write DVD-RAM, offered only as so-called Super Multi burner. A Super Multi - burner is a device that can handle all DVD formats. This DVD burner offered since 2004 at prices similar good DVD ± RW burner (without DVD-RAM) and impress with their technical performance and customers who use the DVD burner exclusively for DVD ± R and DVD ± RW. The clearest indicator of this situation is that some dealers sell while DVD-RAM -capable burner, but only offer DVD ± R discs and DVD ± RW media and not DVD -RAM media.

This situation has occurred because the manufacturers of DVD -RAM devices barely afford public relations for the DVD-RAM. For example can be found on the website of the manufacturer does not normally enlightening presentations on the benefits of DVD-RAM. Also in the instructions of the devices lack such depictions. DVD-RAM is therefore used in the computer field only by insiders, although they allow a much greater data security and an easier to use than a DVD ± RW.

Intended successor

Theoretically it would be possible to equip the DVD-RAM in addition to the two-sided use currently possible with several layers - similar to DVD ± R Dual Layer and Double Layer. It was, however, deviate from this way to focusing more on the so-called next generation of optical media. Existed to the designated successor of HD DVD-RAM, HD DVD Group for the DVD-RAM. The capacity of this medium should be about 20 GB for single-layer and double-layer discs at about 32GB. The basic properties of the DVD-RAM remained. In general, HD - DVD drives backwards compatible with DVD-RAM, that is, the storage media DVD-RAM can be used directly without copying. The development of HD - DVD players with HD DVD - RAM support, however, was terminated due to the task in the format battle with the Blu- ray Disc. In contrast to HD DVD, Blu -ray consortium provides no counterpart, although the use of UDF version 2.5 should allow the inclusion of BD -RE as a removable disk as a file system (ie as a software implementation).

Differences between the DVD-RAM to DVD -RW and DVD RW

In addition to the DVD-RAM there are two other rewritable DVD formats, DVD-RW and DVD RW. Although similar in appearance, name and capacity, the differences are serious. Generally speaking, the main difference from the DVD ± RW to a DVD-RAM is that the DVD ± RW is designed for maximum compatibility with the DVD-Video and DVD-ROM, while the DVD-RAM has been optimized for data security. The differences in detail:

Differences between the DVD - RAM MO disk

In the literature, the DVD-RAM is often mistakenly viewed as an MO variant, because in both the sectoring on the disk surface is visible (compare the first and second imaging systems, in particular the magnification). The sectorization is a higher reading and writing accuracy. The sectoring can, however, use various techniques: The DVD-RAM used as a read-write method, the phase -change technology, while the MO disk using the magneto- optical technique. For more differences between the DVD - RAM MO disk, see under the heading of Magneto Optical Disk

Differences in the DVD-RAM of DVD-Video

A DVD-RAM can be used as a DVD- Video, so can also be stored videos on it and comes with a DVD menu. On DVD players that can read DVD-RAM, they can also be played without any problems.

When videos are not written to the PC, but a DVD - VCR to a DVD- RAM, so there are differences. Specifically: A recorded on a DVD - Video DVD - RAM is not available on the PC directly to a DVD ± R or DVD ± RW umkopierbar and then on any DVD - player, because this, first the video file to be converted.

The DVD - RAM video recorder using the First another directory structure. Are the videos of the DVD-Video ( as with DVD ± R and DVD ± RW) in the VIDEO_TS directory, this directory is in the DVD-RAM, however DVD_RTAV. Second, the file format used for video data is different. The video is not stored in the file format but in VOB VRO (Video Recording Object). The VRO file format allows a better recording and video editing, but it is not compatible with traditional DVD players. The current DVD player software for PC such as WinDVD or PowerDVD can now play DVD - RAM video files directly without conversion. In 2004 there was not a single DVD - Video Recorder with DVD-RAM, which is directly generated at the user's VOB files so that they can be transformed by a simple PC copying actions into a DVD ± R. With some recorders, but you can now choose the recording format.

A special aspect / utility

It is rarely considered that more and more ( higher ) HDD / DVD recorder and also pure DVD recorder DVD-RAM describe, but at least can also read.

In many such recorders, it is possible to " commute " to make DVD-RAM for writing and reading even. It may be concluded that the manufacturer of such consumer devices may be largely in terms of the format to be agreed.

Very little is known of the utility of DVD-RAMs in the transfer recordings to a PC. Some video editing programs such as COREL or Pinnacle allow you to select not only individual complete recordings, but even individual chapters from it and transferred to the PC for processing. Other video editing programs have been importing DVD-RAM despite customer requests still not implemented. Pure software players can often represent the contents of a DVD - RAM to choose by title and chapter.

The often very reasonable discount rates (<1 EUR ) for DVD-RAM from brand manufacturers leave the first as permanently scheduled archiving to DVD-RAM seem interesting. In contrast to finally burned DVDs can delete uninteresting parts that have become again. Then the liberated part of a DVD-RAM is immediately available otherwise. DVD -RW discs hold on this point a comparison was not because their not infrequent errors, as they are not to be feared for DVD - RAM.

Specification of the media

The knowledge of the specification of the data carrier is useful in the evaluation of the DVD-RAM technology, the purchase of the DVD-RAM devices and media. In the following, only the information is presented, which are of immediate general interest. Pure technical details on over 100 pages are shown in the sources, which are given in Chapter norms and standards.

The DVD -RAM media is available in two different diameters: Once in the diameter of a CD of 120 mm in diameter and a mini CD of 80 mm. First, the typical DVD-RAM specification should be treated on the basis of capacity, equipment, write protection, and file system.

  • DVD-RAM Version 1.0: unilateral medium with a layer and a capacity of 2.40 GB
  • Two-sided medium with one layer and a total capacity of 4.81 GB
  • Unilateral medium with a layer and a capacity of 4.38 GB
  • Two-sided medium with one layer and a total capacity of 8.75 GB
  • Speed 2x
  • Revision 1.0: Speed ​​3x
  • Revision 2.0: Velocity 5x
  • Revision 3.0: Velocity 6x max
  • Revision 4.0: Speed ​​8x max
  • Revision 5.0: 12x max speed
  • Revision 6.0: Speed ​​16x max
  • Class 0: speeds of 2x to 5x. This is the original format class. These media can be read and written from Class 0 and Class 1 devices. As a phase-change material germanium, antimony and tellurium ( GeSbTe ) is in the 1x, 2x and 3x media used, the color is golden brown. 5x - media consist of the same material as class -1 media, a reduction in the write cycle (see Class 1 ) with the result. Right now ( February 2008) are, however, also available with DVD-RAM 5x speed, which are designed for a write cycle rate of up to 100,000 ( golden brown color, so GeSbTe as Phase Change Material ).
  • Class 1: speeds of 8x to 16x. The older class 0 devices can these media read but not write. As a phase-change material here Bismuth Coupling Material (BCM ) is used, whereby the write speed could be indeed increased, but the number of possible write cycles had to be reduced from 100,000 to 10,000. The color of these media is dark green. The introduction of this format was announced in March 2005 to increase the speed. Although by now (February 2007 ) Drives are offered that support this format class and can describe with up to 12x speed according to the manufacturer, these media so far (January 5, 2008), however, are not available.
  • Option I: This DVD -RAM media type was the first existing. With him, the one-or two -sided DVD - RAM is firmly in protective packaging that resembles a 3.5 " floppy disk. This packaging is also referred to as a caddy or cartridge and protects the DVD-RAM primarily against scratches and dirt. The cartridge does not protect completely against sunlight and dust, so they can be inserted ( made ​​of thin plastic or cardboard) during prolonged storage in the included case. Variant I is particularly widespread in DVD-RAM video recorders, because here the consumer can handle the DVD-RAM rather careless and drop. The variant I is referred to as Type I. Variant II is clearly visible the red slide switch for write protection.
  • Variant II: As Variant I, but the DVD-RAM can be removed from the cartridge when needed. This is useful because many newer DVD -RAM device - especially in the computer field - for a simpler and therefore cheaper mechanics do without the ability to read a DVD -RAM with a cartridge. This variant offers the best protection with maximum flexibility. The variant II is also known as Type 4.
  • Variant III: In this variant, the DVD media is shipped in a plain jewel case or slim case. With a careful use, the lack of permanent protection of DVD-RAM with a cartridge hardly a problem, similar to that in the known CD -R and DVD ± R is the case. The media of the " variant III " are significantly cheaper than those of the variants I or II at an additional cost, there is also this design with scratch-resistant surface to ensure more durability in daily use.
  • Variant IV: Meanwhile, there are a handful of DVD- RAM media in Cakebox, which are priced slightly cheaper again because for you the jewel case or Slimcases missing. To what extent the stacking of the media affect these in quality, is still unclear. It is certain at least that the media should not be stacked after the first use; for maximum data security, they are then kept individually in protective cases.
  • Drivers: Each DVD - RAM media has a write-protect bit, which allowed regardless of the file system to write protect the entire medium. This write protection is on the hardware side observed from the drive. To activate or deactivate write protection of this special software or driver is needed. In a virus-infected environment, the write protect bit offers no protection if the medium is still unprotected and it has to be inserted to activate only in a drive. In short: For such cases is a write protection suitable, which can be activated by hand without the aid of software, such as the slide switch or by a special drive.
  • Slide switch: A DVD - RAM media itself has no mechanical write protection. At cartridges but there is a write protect slide switch similar to the 3.5 " floppy disk. This switch is of course only valid if the DVD - RAM is used with a cartridge. Most newer drives can a DVD - RAM media but often only load without cartridge, so that the elegant slide switch does not protect in all cases.
  • Drive 1: DVD -RAM media, the only ever be used without a cartridge, a very secure and easier to use makeshift ad hoc write protection is to use a second drive that read DVD-RAM only may or may not write. In this second drive is a DVD -ROM drive that can also read the DVD format DVD-RAM, see chapter on device manufacturers ( see below).
  • Drive, 2: Since the DVD - RAM is a casual one data security medium, had some drives (eg Panasonic LF- D201 ) in a device firmware persistent adjustable switch which according to the factory settings without cartridge media (or of their media removed ) read-only treated as due to possible contamination. This setting can be set as a user with supplied by the equipment manufacturer specialized software according to their needs (eg Panasonic LF- D201: RAMDiscTool ).

Software -side support

UDF is the most appropriate format for formatting DVD-RAM, it is supported by Windows Vista and Windows 7. Are on Windows XP and earlier Microsoft OS has a separate driver installed ( many drives InCD is this Nero AG enclosed). DVD-RAM can indeed use it works with FAT and NTFS, but then are more common error, since deleted blocks are discharged from these not reliable from the TOC.

Device types, producers and RAMPRG

A current list of manufacturers of DVD-RAM is to get over the so-called RAM Promotion Group, which made ​​efforts since the IFA 2003 to market DVD-RAM jointly active. The RAMPRG members include the following manufacturers: Hitachi, JVC, Toshiba, Maxell, LG Electronics, Panasonic (Matsushita ), Samsung, Verbatim and TEAC.