Recordable DVD formats
Summary Description Newswire's 5 Minute Guides looks at DVD-RAM and other standards in the confusing recordable DVD market.
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Roullas Top10 Simon Vandore

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Editorial InformationArticle Location
Article Topic 5 Minute Guides
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Story Group 001001
Post Date 25/09/2000 04:41 AM Status Posted Entered by Simon Vandore on 20/09/2000 08:55 AM


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What's this DVD-RAM? Don't you mean DVD-ROM?
No, DVD-ROM is a read-only standard used in most current DVD drives on PCs, whereas DVD-RAM lets you record information to a DVD. ROM stands for read-only memory, while RAM stands for random access memory, but DVD-RAM has nothing to do with the RAM (DRAM, SDRAM, etc) that your computer uses to store information every few nanoseconds. The name DVD-RAM simply refers to the ability to write and rewrite information to a DVD.
Is there a DVD-RAM standard?
That's the trouble. There are several recordable DVD formats from competing manufacturers, although DVD-RAM was the original proposal. Some may end up being aimed more at the lounge room as a replacement for VCRs, but all are capable of being used for computer data. The others are DVD-R, DVD-RW and DVD+RW.
Most DVD standards are devised by the DVD Forum, an industry organisation which is more of a working group formed by several companies than an official standards body. In 1999, the Forum moved to version 2 of the DVD-RAM specification, raising the capacity of a standard disc from 2.6G to 4.7G (all competing formats now aim to match this capacity). There are also double-sided DVD-RAM discs which hold up to 9.4G. By comparison, rewriteable CDs only store up to 700M.
Hitachi, Panasonic and Toshiba have backed DVD-RAM and have all shipped drives using the format, to mixed reviews. DVD-RAM discs can be rewritten about 100,000 times.
What about the other formats?
Discs using the DVD-R format can be used only once to record data (just like CD-R) and can hold up to 4.7G. DVD-R is not a format likely to reach consumers, but Pioneer used DVD-R to develop DVD-RW. This format also holds 4.7G and can be rewritten about 1000 times. Theoretically DVD-RW can be read by many DVD-ROM and DVD video drives, but the discs from Pioneer's current consumer machines use a new video format that is incompatible with older DVD video players.
Hewlett-Packard, Sony and Philips have collaborated to produce an alternative called DVD+RW which records using the DVD video format, although it's not supported by the DVD Forum. DVD+RW is designed to be more compatible with current DVD-ROM drives -- its discs use the same sector and error correction code (ECC) block layout, the same modulation code and a similar logical layout. DVD+RW is designed to store three or six gigabytes. However, the attempt at compatibility was not fully successful and to read DVD+RW discs the standard will have to be implemented on the microcontrollers in newer DVD-ROM drives.
What are the advantages of recordable DVD formats?
The discs cost very little to make, just like CDs and other DVDs, which means that even if the cost of a drive is high, it should easily pay for itself in the long term compared to proprietary removable storage formats. Even the first generation of DVD-RAM, when drive prices were incredibly high and capacity was only 2.6G, offered a cost per megabyte far lower than any other rewriteable storage medium (1.5 to 2c per M). As DVDs become as commonplace as CDs, the ability to record (and re-record) many gigabytes of information on such a cheap medium will be of great advantage.
How's the market looking for recordable DVD drives?
Unfortunately most product releases so far have been late to market and the drives remain very expensive, but DVD-RAM is winning the race among early adopters in the US. DVD+RW may pick up speed later this year or early next year as its backers release drives with superior features, winning friends in the compatibility stakes. Many DVD-ROM drives can't read DVD-RAM discs -- Panasonic and Hitachi were the first to produce multi-format readers.
On the other hand, current recordable DVD drives hold only a tiny fraction of the rewriteable storage market and even the strongest industry forecasts give the format less than 10 percent market share by the end of 2001. Predecessors like recordable CD (CD-R and CD-RW) drives and DAT (digital audiotape) are firmly entrenched and still selling well.
Hitachi has predicted that DVD-RAM will offer 45G per side by 2005. Toshiba puts it at 50G. At the end of the day, consumers may end up deciding whether we ever reach these heights.


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Newswire's 5 Minute Guides looks at DVD-RAM and the confusing recordable DVD market.

WAP SummaryRecordable DVD formats
Newswire's 5 Minute Guides looks at DVD-RAM and the confusing recordable DVD market.

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Recordable DVD formats

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