Professional Disc for DATA

Professional Disc for DATA (PDD or ProDATA) is a recordable optical disc format which was introduced by Sony in 2003. It was one of the first two formats (along with Ultra Density Optical) to utilize blue-violet lasers for reading and writing, which allowed for much higher density data to be stored on optical media compared to the higher wavelength red laser technology used in the CD and DVD formats.

=Technology=

PDD uses a 405nm wavelength and a numerical aperture (NA) of 0.85 for the laser, allowing 23GB of data to be stored on one 12cm disc - the equivalent to nearly five single-layer DVDs, and a data transfer rate of 11MB/s for reading and 9MB/s for writing. Plans have also been made to introduce dual-layer 50GB and quad-layer 100GB discs in the future.

Confusingly, this all sounds very similar to the Blu-ray Disc format, another optical disc format using blue-violet lasers which is also supported by Sony. Even the discs caddies look very similar between the two formats. The only apparent difference is that single-layer PDD discs have a capacity of 23GB whereas Blu-rays can store 25GB. However, Blu-ray discs only currently allow a data transfer rate of 4.5MB/s - much lower than PDD. This is because PDD discs use much higher quality media and drives use higher quality components, making them prohibitively expensive for the average consumer segment Blu-ray is aimed at.

=Applications/Products=

PDD drives and media became available in mid-2004; the format was aimed primarily at small and medium-sized enterprise for data archival and backup. The BW-RS101 external SCSI-3 drive originally retailed in the UK at £2,344 (excl. VAT) directly from Sony, and 23GB write-once and re-writeable media retailed for £30 each. Two other drives - the BW-F101/A internal SCSI drive and the BW-RU101 external USB 2.0 drive also became available around the same time.

=See also=

Blu-ray Disc

HD DVD

Ultra Density Optical

Optical disc

=External links=

*[http://www.sony.net/Products/MO-Drive/ProDATA/index.html Sony Global - Professional Disc for DATA] *[http://www.sonyburners.com/prodata/index.php Sony Storage Solutions - ProData]