8 ings You Didn t Know About XDCAM Discs

[1] They're not actually called XDCAM Discs Strictly speaking, XDCAM isn't actually a type of storage device, but instead is a recording format introduced by Sony in 2003. What people are actually referring to is called a Professional Disc. However as the sole pro-camera manufacturer to use Professional Discs, and only on their XDCAM camera range, they quickly became synonymous with the recording format.

[2] 1,000 write and re-write cycles Thanks to non-contact recording and playback (the read/write head never makes contact with the disc surface), the rewritable discs support up to 1,000 read/write/erase cycles. That's about 3 years of pretty heavy use.

[3] They're based on the same technology as Blu-Ray discs Professional Discs (PFDs) make use of an optical disc and a laser to store data, much like CDs and DVDs. However, where they use infrared and red laser technology respectively to write to the disc, PFDs utilise blue-violet laser (the same as Blu-Ray discs). The electromagnetic radiation emitted from the blue-violet wavelength allows for a much higher density of data to be stored, compared with CDs or DVDs.

[4] It's a recording medium that doubles as a tapeless archive Despite an industry making huge leaps and bounds in online/cloud based video production, a lot of videographers still like to see a physical stack of tapes or drives sat in a cupboard or under their desk. The write-once 128GB discs are an efficient method of recording/archiving as there's no need to transfer the media onto another device after filming. Sony also claims a shelf life of 50 years, although this is yet to be properly proven, given that the formats only been around for a decade.

[5] Limited read-write speed to approximately real-time The first disc reader Sony launched (PDW-U1) had just one set of read heads, limiting the data access rate to near real-time. So for 3 hours of footage, it took just as long to transfer data from the disc. With an updated reader (PDW-U2), read speeds are increased to around 2.5x, however writing to the discs is still limited to around 1.5x. Other reader-recorders are available, however costing around six times as much youve got to be pretty invested in the XDCAM workflow to justify the expense.

[6] They only have 1 moving part The spinning disc. By keeping moving parts to a minimum, the discs are very reliable. The plastic housing also prevents damage from dust and makes them resistant to a reasonable amount of shock treatment.

[7] When writing data, the temperature can hit 800 c Data on the optical disc is recorded using a phase change' process that momentarily heats a tiny area of the disc surface to a temperature of 400-800 c. The resulting recording is very stable and is able to resist extreme high and low temperatures when recording in harsh environments.

[8] You can store any computer file on the discs Sonys PDW-U1 Professional Disc drive is an external drive that connects via USB 2.0 to Windows or Mac OS X computers using the included free software from Sony. In a firmware and software upgrade in late July 2009, Sony added the ability for users to store any computer files on the Professional Disc; much like a standard DVD. Though it's fair to say that adoption as an alternative to DVDs, USBs or even SD cards hasn't taken off. Still, it's a useful addition for videographers using it on their production when they use the drives to ship media around.

LINK:	http://aframe.com/blog/2013/10/07/8-things-you-didn-t-know-about-xdcam...
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