Professional Disc for DATA
Encyclopedia

Professional Disc is a digital recording
Digital recording
In digital recording, digital audio and digital video is directly recorded to a storage device as a stream of discrete numbers, representing the changes in air pressure for audio and chroma and luminance values for video through time, thus making an abstract template for the original sound or...

 optical disc
Optical disc
In computing and optical disc recording technologies, an optical disc is a flat, usually circular disc which encodes binary data in the form of pits and lands on a special material on one of its flat surfaces...

 format introduced by Sony
Sony
, commonly referred to as Sony, is a Japanese multinational conglomerate corporation headquartered in Minato, Tokyo, Japan and the world's fifth largest media conglomerate measured by revenues....

 in 2003 primarily for XDCAM
XDCAM
XDCAM is a a series of products for digital recording using random access solid-state memory media, introduced by Sony in 2003. Four different product lines — the XDCAM SD, XDCAM HD, XDCAM EX and XDCAM HD422 — differ in types of encoder used, frame size, container type and in...

, its new tapeless camcorder
Tapeless Camcorder
A tapeless camcorder is a camcorder that does not use video tape for the digital recording of video productions as 20th century ones did. Tapeless camcorders record video as digital computer files onto random access data storage devices such as optical discs, hard disk drives and solid-state flash...

 system. It was one of the first optical formats to utilize blue laser
Blue laser
A so-called blue laser is a laser that emits electromagnetic radiation at a wavelength of between 360 and 480 nanometres, which the human eye sees as blue or violet. Diode lasers which emit light at 445 nm are becoming popular as handheld lasers. Light of a shorter wavelength than 400 nm is...

, which allowed for higher density of data to be stored on optical media compared to infrared laser technology used in the CD and red laser technology used in the DVD
DVD
A DVD is an optical disc storage media format, invented and developed by Philips, Sony, Toshiba, and Panasonic in 1995. DVDs offer higher storage capacity than Compact Discs while having the same dimensions....

 format.

Technology

PFD uses a 405 nm wavelength and a numerical aperture
Numerical aperture
In optics, the numerical aperture of an optical system is a dimensionless number that characterizes the range of angles over which the system can accept or emit light. By incorporating index of refraction in its definition, NA has the property that it is constant for a beam as it goes from one...

 (NA) of 0.85 for the laser, allowing 23 GB
Gigabyte
The gigabyte is a multiple of the unit byte for digital information storage. The prefix giga means 109 in the International System of Units , therefore 1 gigabyte is...

 of data to be stored on one 12 cm disc – the equivalent to nearly five single-layer DVDs, and a 1x speed data transfer rate of 88 Mbit/s for reading and 72 Mbit/s for writing. After the 23GB disc was released, a dual-layer 50 GB was developed and released.

This format is sometimes confused with the Blu-ray Disc
Blu-ray Disc
Blu-ray Disc is an optical disc storage medium designed to supersede the DVD format. The plastic disc is 120 mm in diameter and 1.2 mm thick, the same size as DVDs and CDs. Blu-ray Discs contain 25 GB per layer, with dual layer discs being the norm for feature-length video discs...

 format, another optical disc format using blue-violet lasers and supported by Sony. Even the PFD's caddy and Blu-ray's bk prototype caddy (later dropped) looked very similar. Capabilities differ; single-layer PFD discs have a capacity of 23 GB whereas Blu-rays can store 25 GB. However, Blu-ray Discs currently allows a 2x data transfer rate of 72 Mbit/s – lower than PFD. This is because PFD discs use much higher quality media and drives use higher quality components, making them prohibitively expensive for the consumer segment to which Blu-ray is aimed.

XDCAM video system

The PFD format is used as the recording medium in Sony's XDCAM
XDCAM
XDCAM is a a series of products for digital recording using random access solid-state memory media, introduced by Sony in 2003. Four different product lines — the XDCAM SD, XDCAM HD, XDCAM EX and XDCAM HD422 — differ in types of encoder used, frame size, container type and in...

 professional video devices, both for standard definition and high definition applications.

Professional Disc for Data (PDD)

Professional Disc for DATA (PDD or ProDATA) was a general-use recording media variant of PFD, aimed primarily at small and medium-sized enterprise for data archival and backup
Backup
In information technology, a backup or the process of backing up is making copies of data which may be used to restore the original after a data loss event. The verb form is back up in two words, whereas the noun is backup....

. PDD drives and media became available in mid-2004. The BW-RS101 external SCSI-3 drive originally retailed in the UK
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...

 at £2,344 (excl. VAT
Vat
Vat or VAT may refer to:* A type of container such as a barrel, storage tank, or tub, often constructed of welded sheet stainless steel, and used for holding, storing, and processing liquids such as milk, wine, and beer...

) directly from Sony, and 23 GB write-once and re-writeable media retailed for £30 each. Two other drives – the BW-F101/A internal SCSI
SCSI
Small Computer System Interface is a set of standards for physically connecting and transferring data between computers and peripheral devices. The SCSI standards define commands, protocols, and electrical and optical interfaces. SCSI is most commonly used for hard disks and tape drives, but it...

 drive and the BW-RU101 external USB 2.0 drive also became available around the same time.

On March 31 2007, Professional Disc for DATA reached their "end of life".http://www.sony.net/Products/MO-Drive/ProDATA/ PFD are still being manufactured and used in Sony XDCAM devices. Sony states that PDD and PFD media are not compatible, but does not specify the exact differences between products.

Sony's PDW-U1 Professional Disc drive is an external drive that connects via USB 2.0 to Windows or Mac OS X computers using Sony's freely included software. In a firmware and software upgrade in late July 2009, Sony added the ability for computer users to store any computer files on the Professional Disc. http://forums.creativecow.net/thread/142/866275#866289

External links

The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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