What do the letters after various CD specifications mean?

DVD-RAM is a writable DVD standard jointly launched by Pioneer, Hitachi and Toshiba, which uses a technology similar to CD-RW. However, due to the difference of medium reflectivity and data format, most standard DVD-ROM drives cannot read DVD-RAM disks. The DVD-ROM drive that can read DVD-RAM disks was first introduced at the beginning of 1999, and both DVD-ROM and DVD players that meet the Multi-Read 2 standard can read DVD-RAM disks.

The first DVD-RAM drive was launched in the spring of 1998, with a capacity of 2.6GB (single-sided) and 5.2GB (double-sided). 14.7GB disk came out at the end of 1999, and double-sided 9.4GB disk was put on the market in 2000. The DVD-RAM drive can read DVD video, DVD-ROM and CD.

The advantage of DVD-RAM is that the formatting time is very short, less than 1 minute. The formatted CD can be written and erased without special software, which means that it can be used as easily as a floppy disk and is cheap, but it is only suitable for computers with related drives. From this point of view, compared with other DVD recorders, DVD-RAM is more like a special and high-performance product like MO.

DVD-RW

DVD-RW standard was put forward by Pioneer Company in 1998, and was strongly supported by DVD forum. Its members include Apple, Hitachi, NEC, Samsung and Panasonic, and the formal standard of 1. 1 was completed in mid-2000. DVD-RW products were originally located in consumer electronics products, which mainly provided functions similar to VHS video tapes, and could record high-quality multimedia video information for consumers. But with the development of technology, the function of DVD-RW has been gradually extended to the computer field. The principle of DVD-RW recording is similar to that of ordinary CD-RW recording, and it also adopts phase-change reading and writing technology, which is also the recording method of fixed linear speed CLV.

The advantage of DVD-RW is its good compatibility. It can save data in DVD video format, so it can be played on DVD players. However, its big disadvantage is that it takes one and a half hours to format. In addition, DVD-RW provides two recording modes: one is called video recording mode; The other is called DVD video mode. The former mode is rich in functions, but it is not compatible with DVD players. Users need to choose between these two formats, which is not very convenient to use.

DVD+RW

DVD+RW is the easiest DVD recording standard to use, the best compatibility with existing formats, and the price is cheap. The DVD+RW standard was jointly formulated by Ricoh, Philips, Sony, Yamaha and other companies, and the industrial organization of DVD+RW alliance was established. DVD+RW is the only rewritable format that is completely compatible with existing DVD players and DVD drives, that is, it is completely compatible with real-time video recording and random data storage in computer and entertainment applications. DVD+RW can not only be used as data storage of PC, but also can directly burn video information in the format of DVD video, which is a great breakthrough in DVD industry. With the development and popularization of DVD+RW, DVD+RW has become a rewritable DVD standard that closely combines DVD video with DVD burner on PC.

Features of DVD+RW:

Single-sided capacity of 4.7GB；; Double-sided capacity 9.4GB

Video with a maximum recording time of 4 hours on one side; 8 hours each.

The laser wavelength is 650 nm, which is the same as DVD video.

Data density at constant linear velocity

CLV and CAV combustion

UDF file system (universal disk format)

Quick format

Sequential combustion or random combustion

Lossless link (multiple recordings will not waste disc space)

After firing, all physical parameters conform to DVD-ROM specifications.

DVD+RW has the ease of use of DVD-RAM optical drive, and improves the compatibility of DVD-RW optical drive. Although the formatting time of DVD+RW takes about one hour, it can be formatted in the background from the middle, so you can start burning data in one minute, which is the fastest practical DVD burner. . At the same time, DVD+R/RW standard is the only DVD recording standard supported by Microsoft.

DVD- multimedia

Because DVD-RAM, DVD-RW and DVD-RW are incompatible with each other, users are often troubled by the design and compatibility of DVD-related software and hardware. There is an urgent need for a unified DVD recording standard, but a unified specification has never been established, and the dispute among the three specifications of DVD recording standard continues. In order to solve the compatibility problem to a certain extent, Matsushita of Japan put forward the idea of DVD-Multi in the "DVD Forum" in September 1999, hoping to solve the confusion of DVD specifications, and determined the main specifications in September/20001. DVD-Multi technology takes DVD-RAM as the main architecture and is compatible with DVD-RAM, DVD-R, DVD-RW, CD-R/CD-RW, etc. Strictly speaking, DVD-Multi is not a technology, but a design specification that combines the audio and video of "DVD Forum" with the recording specification, which is a product derived from the combination of the first two DVD recording specifications. DVD-Multi supports DVD-Video, DVD-ROM, DVD-Audio, DVD-R/RW, DVD-RW, DVD-RAM, DVD-VR and, of course, CD-R/RW. Because DVD-RAM and DVD-R/RW are two highly complementary standards, it is very important to combine them. Therefore, it has been supported by many top manufacturers, including Hitachi, Panasonic, mitsubishi electric, Intel, LG Electronics, NEC, Pioneer, Samsung Electronics and Sharp.

Double DVD

The DVD-Dual specification, also known as the DVD-Dual RW standard, was designed and initiated by Sony Corporation. Manufacturers, including Sony and NEC, put forward a new specification for DVD Dual, namely the design of DVD R/RW, in view of the incompatibility between DVD R/RW and DVD R/RW. DVD Dual does not have the same unified specifications as DVD Multi, which allows manufacturers to play freely. DVD RW burner can be compatible with DVD-/RW and DVD+ RW, so users don't have to worry about the matching of DVD discs.

However, the DVD dual burner also has a small disadvantage, that is, it needs to pay two patent fees, the production cost will increase a little, and the price will naturally be more expensive. In contrast, since DVD-RAM and DVD-R/RW are official DVD forums, they should have advantages in this respect. At present, most Japanese and European and American manufacturers focus on DVD-Multi, while most manufacturers in China and Taiwan Province Province focus on DVD-Dual.