Double Density CD - Page 3

- How did done it?

The high capacity of the Double Density CD format is realized by a few simple modifications to the common CD format. In order to increase data density, track-pitch and minimum pit length are miniaturized to increase the data capacity from 650MB to 1.3GB. This capacity is achieved by utilising a conventional 780 nm laser and using a NA of 0.50 or 0.55, thus reducing the track pitch (by 1.45) and the minimum pit size (by 1.33):

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To accommodate higher physical bit density, a parameter in the error-correction scheme (CIRC) has been changed, and the address format (ATIP) has been expanded. Sony stated in the original press release that "...A copy control scheme will be included in the format to meet the increasing demands for secure content protection...".

This copy control scheme, as we can understand, means that you can not write AudioCD format in DDCD-R/RW media! Yeap folks. Sony denied any relation of the DDCD format with Audio CDs (and with all possible piracy issues). Just imagine that a DDCD-R media will be able to store 148mins of music... Someone might say that this is not a real problem since DDCD media is not playable from current stand alone players/CD-ROMs. That is true for the present situation, but what about the future? Sony's future CD-ROMs/CDR-W drive will probably support the DDCD format, and then this *problem* will become a reality. Of course you are able to write Mp3 files (as data tracks).

- Use

The product sheet of CRX200E model says that you can:

- Backup your most important files
- Store large or high quality digital photos
- Move your favorite music tracks from your HD
- Store 2 hours MPEG-1 digital motion pictures
- Store Internet homepage's multimedia contents
- Distribute and share data

Have you noticed that almost every single use contains the word "store" and "backup"? This is where the DDCD is aimed at!