DVD Jukeboxes | DVD-RAM Overview | DVD-RAM Specifications | DVD-RAM Media Overview DVD (Digital Versatile Disc or Digital Video Disc depending on who is shouting loudest about trademarks and patents) is the latest cheap & portable optical storage technology that has taken hold of the computer and home entertainment markets. Like its smaller capacity cousin the conventional CD, DVD seemed certain to become the mainstream medium for storage, video, music and computer software and backup of its generation. In terms of factory manufactured DVDs (pre-recorded) this has already occurred. Unfortunately, the domination of the backup and recordable market has not been quite successful, mainly due to the inability of international manufacturers to behave like adults and co-develop formats. CD Recording has become one of the most popular formats for the quick exchange, urgent replica, and long-term archiving of business & consumer data, with the one obvious and serious downside: the capacity. Optical technology in the form of CD's simply does not provide enough room. With the widespread adoption of CD Recording technology, has come the long awaited release from the restraints of the ubiquitous floppy drive. For those who replication needs are mixtures of high volume but lower capacity, recordable CD-ROM media is an ideal solution. Recordable CD-ROM media has also assisted in eliminating one giant and further headache known to most people who have at one time needed to backup data: the dreaded compatibility issue. The CD Writer has come a long way in a very short space of time. The first single-speed models may be only a few years old, but already they seem like ageing dinosaurs from a half-forgotten era that still remembers the 386 and Pentium I. CD Rewriters expanded the market even further, and with 4xspeed (gasp), then 6xspeed (incredible!) and beyond to infinity (and with prices dropping faster than even RAM ever tried to in its heyday), CD Recording has become a normal and simple process for countless users. Grandmothers tut over their knitting as they get a 'buffer overload' error in the background. Fast on the heels of the CD Recording systems in the portable storage race is DVD technology. DVD recorders in the guise of DVD-RAM, DVD-R, DVD-RW, PD and a host of other standards are encroaching into this once unassailable territory. The choices suddenly don't seem so clear-cut anymore. Which technology are you better off with? Which version of optical platter technology should you select? The choices can be narrowed down far more simply and quicker than they seem at first sight. To isolate DVD-RAM for a moment and ignore alternatives such as recordable CD media, the first step is to understand the variations between DVD standards and clarify the media hype over incompatibilities. DVD-RAM is one of many solutions available to create, read, and rewrite DVD and CD discs. There are many standards at the moment, which at first may seem a little unrelated or even confusing, however there is a pathway to the technology and there is compatibility between products. It is important that you understand which DVD drives use which media and how their interoperability and compatibility between platforms can be used. For more information on this subject with a simple and clear graphic depicting the various technologies and their compatibility's, see our Guide To DVD Drives: Competing Standards. The first available DVD-RAM drives on the market were primarily based on the CDL110 series of mechanisms manufactured by Panasonic (Matsushita/Technics), and it and its successors still power a large proportion of the DVD-RAM drives today. We can supply both internal and external DVD-RAM drives if you really, really want one. Universal Format & Compatibility The DVD-RAM disc use similar technology as CD-ROM. It is a 12 cm disc which can be read from or written to on DVD-RAM drives and read from new DVD-ROM drive (fourth generation and above). The DVD-RAM drive can read all existing 12 cm discs : CD-ROM, CD-R, CD-RW, DVD-ROM and DVD-RAM. DVD-Video requires separate MPEG-2 decoder (hardware and/or software). Reliability DVD-RAM media is not susceptible to magnetic fields. The drive writes and reads with an extreme accuracy. There is no physical contacts between the laser head and the media eliminating conventional media damage problems. DVD-RAM discs have an industry recommended minimum 50 years life. High Storage Capacity Capacity availability to store up to 5.2 GB or 9.4GB on a 12cm disc. Cost effective media with a comparative cost of less than 1¢ (US) per MB. Using the UDF file format you may use your DVD-RAM drive as easily as a hard disk drive attached to your computer, allowing drag and drop action similar to that of a CD-RW but with greater capacity. Typical Specifications The following information provides a general guide as to the capacity, performance, and compatibility of DVD technology when comparing backup and archiving technologies Buffer capacity: 256KB to 2MB per drive unit Interfaces: SCSI-2 (Fast/Ultra), LVD Reading compatibility: CD-ROM CD-ROM XA CD-R CD-RW CD-DA (audio) Photo-CD Video-CD CD-G DVD-R DVD-ROM DVD-Video DVD-RAM PD cartridge Writing compatibility: DVD-RAM PD cartridge Average seek times per drive unit: DVD-RAM : 180 ms DVD-ROM : 260 ms CD-ROM : 150 ms DVD-RAM : 120 ms DVD-ROM : 95 ms CD-ROM : 95 ms PD cartridge : 95 ms Average Synchronous Burst transfer rate: 10MB/s Average Asynchronous Burst transfer rate: 5MB/s Average Sustained data transfer rate: DVD-RAM : 1.385MB/s DVD-ROM : 2.770MB/s DVD-R : 2.770MB/s CD-ROM : up to 2.4MB/s DVD-RAM : 1.385MB/s DVD-ROM : 2.770MB/s CD-ROM : up to 3MB/s PD cartridge : 1.141 MB/s Loading method: Motorised tray Warranty: 1 Year Media: DVD-RAM Disc Overview The DVD-RAM disc can store up to 2.6GB or 4.2GB of data per side. If both sides are activated, the total capacity reaches 5.2GB or 9.4GB (double-side media). If only one side is activated and the other one is neutralised, it's a 2.6GB (one-side media). Each DVD-RAM disc is delivered inserted in a plastic shell - the cartridge - which protects the disc from dusts, scratches and fingerprints. Type I disc : the disc cannot be removed from its cartridge, even for reading it. Only DVD-RAM unit can read this type of disc. Type II disc : the disc can be removed from the cartridge to be read in a DVD-ROM drive (fourth generation and above). But to write data to the disc, it must be placed in its cartridge before insertion into a DVD-RAM drive.   Type II Type I Capacity 2.6GB 5.2GB Sides used Single-sided Double-sided Disc diameter 120mm 120mm Disc thickness 1.2mm 1.2mm Disc centre hole diameter 15mm 15mm Cartridge dimensions 138x125x8mm 138x125x8mm Substrate material Polycarbonate Polycarbonate Recording technology Phase change Phase change Laser wavelength 650nm 650nm Sector size 2048Bytes 2048Bytes Block size 32KB 32KB Minimum data bit length 0.41micrometer 0.41micrometer Sector/Track 17/40 17/40 Track pitch 0.74micrometer 0.74micrometer Weight 90g 90g   Home | Products | Technical Services | Internet Services | Links & Resources Technical Info | Contact | Legal Pages | Privacy Policy StorageWorld© - Copyright 1998-2004 Antony Kershaw