BD-RAM

[Blu-rave]

Will there be BD-RAM discs?

[Blu-Wave]

Like minidisc, Hi-MD and DVD-RAM (and unlike DVD), BD is a data-based format designed to support flexible editing features - look at both minidisc and DVD-RAM for current examples of these. Because of this built-in flexibility, rewritable BD-RWs provide similar abilities in high definition to DVD-RAMs in standard definition, and so largely make them redundant within the BD format (other variants include read only BD-ROM and write once BD-R). However, BD-RAM might be introduced in future for the highest flexibility because the BD specification has been designed to accommodate the fast response phase-change materials used in DVD-RAM if required.

[NThomas76207]

Wouldent BD-RAM be the same thing as BD-RW???

[Blu-Wave]

When CD came out, it was basically a digital version of the LP, with a continuous spiral of pits read from the inside out, similarly DVD was designed as a digital video disc, but late in its development acquired the name digital versatile disc as the realisation grew of its potential outside AV. Unlike CD and DVD, MD (and now Hi-MD) was designed to be a general purpose data storage format, with random access like a hard drive. DVD-RAM uses similar technology to DVD, but is a data-based format, which uses the fastest response phase change materials to give the highest performance of all variants of DVD for trick functions, record whilst play, etc.. This is why Panasonic were able to introduce such functions on DVD-RAM first, and whilst DVD-R etc. may appear to catch up, DVD-RAM is always capable of potentially higher performance.

Like DVD-RAM and MD, etc., BD is a data-based format, and the system has been designed to give effectively BD-RAM-like performance with all variants of BD (except for recording on BD-ROM and re-recording on BD-R). However, for the highest speed recording - such as in computer drives, for example, fast response phase change materials as currently used in DVD-RAM may be employed, if required, and such high speed media might be called BD-RAM ...

[NThomas76207]

Wouldent the DVD-RAM or in now BD-RAM, have to have very, very fast writing speeds?

[Blu-Wave]

Single Head BD drives are expected to go up to around 8-speed (288Mbps/36MBps) for applications that require such data-rates, and commercial 2x media already exist for 72Mbps and twin head 144Mbps (used in professional disc for data [PDD] and XDCAM products). DVD-RAM-type recording materials are available to be used at these higher speeds if required. Using a multi-channel optical head, it should be possible to read from and write to multiple layers at once - probably provided that the layers aren't written at the same position on the disc simultaneously - i.e., that there's a small spatial offset to allow cooling for each layer after each thermal write cycle.