Top Document: comp.arch.storage FAQ 1/2 Previous Document: [6.2.1] CD-ROM Next Document: [6.2.1.2] GIANT CD-ROMS {New} See reader questions & answers on this topic! - Help others by sharing your knowledge From: Disk Digital Versatile Disk (DVD), the new standard, is a two-layer single or double-sided CD, 8.5 or 17 GB, or double-sided single-layer CD, 9.4 GB. Transfer rate is 11 Mbits/sec (1.4 MB/s). http://www.ima.org/forums/imf/dvd/faq.html contains a quick overview. First versions will be read only, later will come WORM, then rewritable. First products are slated to be available by the end of 1996. There were two new standards in the works, digital video disk (DVD) and high-density compact disk (HDCD). DVD was proposed by 8 major consumer electronics giants (including Toshiba, with Time-Warner on board) and would have featured a double sided disk capable of storing 5GB of data per side. HDCD, backed by Philips and Sony, would have held 3.7GB data, with the potential to double them up to hold 7.4GB by using a two-layer technology. VHS/Beta wars all over again, along with issues such as backwards compatability to existing CDs, were avoided, thankfully. In December of 1995, everybody agreed on the new DVD format. See the article by Alan Bell in the July 1996 Scientific American. (John Wiest (john.wiest@24stex.com), gold@sri.com (Michael Gold) and others, 95/04/20, rdv, 96/7/1) My (rdv) notes from the Goddard mass storage conference, 1996: Mike Wingart, Sony, talked about DVD. Their data rate is 11.08 Mbps, though video formats are generally used in a slower mode than that. Two sizes, 8 cm and 12 cm. size single layer, double layer, single side double side 8cm 1.4 GB 5.2 GB 12cm 4.7 GB 17 GB track pitch is 0.74 mm, compared to 1.6 for CD (I wrote mm, but I'm sure that's microns). Starts at the inner hub and moves out as it reads the first layer, when it switches to the second it reverses direction. They are working for backward compatibility, but the CD-recordable format uses a dye polymer that's wavelength sensitive; CD-R is 750 nm, but they are using 650 nm laser. Movie is only 4.8 Mbps (he didn't explain the discrepancy, but I presume they just don't use the extra bw). Video is 3.5 Mbps, the rest is audio (5.1 channels, 3 languages, 4 subtitles). They run 130 to 472 minutes of video on 12 cm disks. Using ISO 13346, the volume & file standard for write once and RW non-sequential media. Using ISO 9660, the CD-ROM FS std, needs some modification to work? DVD-ROM spec 1.0 released Sept. 6th, 1996; others coming soon. Rewritable 2.6 GB single layer requires cartridge to protect disk. Cyclability of rewritable media is still an issue. User Contributions:Top Document: comp.arch.storage FAQ 1/2 Previous Document: [6.2.1] CD-ROM Next Document: [6.2.1.2] GIANT CD-ROMS {New} Part1 - Part2 - Single Page [ Usenet FAQs | Web FAQs | Documents | RFC Index ] Send corrections/additions to the FAQ Maintainer: rdv@alumni.caltech.edu
Last Update March 27 2014 @ 02:11 PM
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