CD is the abbreviation of English Compact Disc, which means high-density disc, that is, optical disc. CD was developed from bakelite records in the late 1970s. After continuous improvement and development, there are more and more kinds of CDs, which have been widely used. So far, there are more than ten specifications of CD products, and each variety has its own standard format. ISO, the international organization for standardization, has formulated and adopted various standards and specifications, and defined important parameters such as the size, rotation speed, data transmission rate and data format of optical discs.

1.CD-DA: laser digital audio disc. Its specification is made in 198 1. Also called CD. The diameter of CD is 12 cm, and each CD can play 74 minutes of high-quality music programs.

2. CD: computer CD. Its specification is made in 1985, which is mainly used for external storage of computers. At first, CD only contained computer-readable text information, but now it can store sound, graphics, video, animation and so on. Disc diameter 12 cm, capacity 650MB.

3.CD-ROM/XA: 1998 has formulated its specifications. When a CD-ROM drive reads a mixed-mode CD (a CD containing both data tracks and audio tracks is called a mixed-mode CD), if it reads computer data, it cannot play music. XA allows computer data and audio data to be placed on the same track, so you can play music while reading computer data.

4.CD-G: also known as karaoke disc, appeared in 1985. It uses the remaining channels on the CD to record some simple still graphics and words (such as lyrics and other data), which can be used for karaoke.

5.CD-V: CD with video, appearing in 1987, is the product of the combination of CD-DA and LD, and is used in DVD players like CD-G.

6. interactive cd-rom: multimedia optical disc system for interactive computer. 1987 has made its specification, and CD-I can only be played by CD-I player.

7.CD-R: recordable optical disc. 1989 formulated its specifications. It can write data in the spare part many times, and is suitable for small optical disc products or data backup and data archiving.

8. Photo CD: Photo CD. 1992 formulated its specifications. Photo CD is specially designed for storing 35mm digital photos. A CD can record about 100 photos for many times, and can be restored to negative when necessary. Photo-CD can be played on CD-I, CD-ROM/XA and Photo-CD players.

9. V-CD: short for Video CD, which means video disc, commonly known as DVD. 1993 formulated the standard of VCD 1. 1. 1994 based on VCD 1. 1, the functions of playing control (screen menu) and high-definition images were added, and the VCD2.0 standard was formulated. The VCD standard adopts CD-ROM/XA data format, so it can be played on the basis of a PC with an optical drive. Ordinary CD players can also play VCD by adding a VCD decoder board. A VCD disc can play video programs for 74 minutes continuously. Its picture quality is better than VHS video, and the sound quality can reach the effect of CD.

10. digital TV interactive technology CD. DVI stores high-quality sound and TV images in a compressed way on an optical disc, also known as a DVI optical disc.

1 1.DVD: High-density digital video disc with a unified specification of 1995. It adopts double-sided optical disc structure, based on single-sided optical disc, each side has a capacity of 4.7GB, and can play MPEG2-2 audio and video signals 133 minutes. At the same time, DVD has variable data transmission rate, the average transmission rate of images and sounds is 4.69 MB/s, the file structure conforms to ISO9660, the data format supports CD-ROM/XA standard, MPEG2-2 audio data compression standard is adopted, PAL resolution is 720×576, 25 frames/s, and Dolby AC-3/5. 1 channel surround sound is supported. Backward compatibility with CDs, VCDs and other optical discs. DVD is used in consumer and computer fields. It is not only a higher density alternative product of video tape, CD and CD-r om, but also a real intersection of personal computers and consumer electronics.

12.LD: Laser disc, also called DVD, so video player is also called DVD player. The diameter of optic disc is generally 30cm, and some are 20cm. According to its signal recording mode, LD can be divided into two types, one is standard video disc (CAV), which plays on one side for 30 minutes. The other is a long video disc (CLV), which plays for 60 minutes on one side.

13.CD-WORM: once written to the disc, the information cannot be modified once written.

14. Erasable optical disk: There are mainly two recording methods: magneto-optical disk (MO) and phase-change optical disk (PCR), both of which are developing rapidly and the storage capacity is increasing.

Note: This answer comes from the webpage:/book/cdgpzlzds.htm. Thanks to the original author.