Can anyone please tell me whats the diffrance between a DVD-R and a DVD+R. Also how much data can I store on a DVD disk.

im not sure if this will help you, but it might. i had asked a friend the same question and this is the response he e-mailed me back. im not sure whee he got the info but whoever wrote it seems to know what they are talking about.

Hehe ... well, there are some who would stand on a soap box with a bullhorn in the pouring rain to give you their opinion on this issue. But stepping beyond that, I'll give you my humble opinion.
In the end, there is very little difference. Here's a summary of all the issues with the formats and why I believe that neither format is superior over the other:

Backward Read Compatibility: At first, when both formats were new, compatibility with various players was debated endlessly. In reality, both formats are pretty much equal, with readability of the -R/+R variety approaching about 85-90% of players. (About 60% for the -RW/+RW discs.) I personally have yet to see any DVD player that will play -R and not +R or vice versa. In my experience, a set top player either will play both or neither.

Write Speed: At first, +R/+RW enjoyed an advantage here. The base writing speed was 2.4x as opposed to -R/-RW's 1x or 2x. This has been somewhat eclipsed now, as all the new writers are now 4x for -R/+R media. -RW media still is written at 2x, while +RW media is still 2.4x.

Media Cost: There are more manufacturers of -R/-RW media, including several inexpensive imported brands. The -R/-RW format has also been around longer, and the blank discs have been in production longer. These reasons make some -R/-RW media cheaper that +R/+RW media. However, when buying quality media from name-brand manufacturers, especially media rated at the new 4x write speeds, the cost difference is minimal to none.

Media Quality: There is wider variation in the quality of -R/-RW media than there is with +R/+RW media. There is really cheap -R media out there that is really only usable with 1x write speeds and even then, still is questionable on some players. Then there is the name-brand -R/-RW media that works great, and then there is media in between. +R/+RW media seems to be manufactured more consistently, and tends to not factor into the playability equation as much.

Standards: -R/-RW is a standard formalized by the DVD Forum, the body responsible for setting standards related to DVDs. +R/+RW is not, it was formulated by an independent consortium of companies, some of which are also DVD Forum members. Heavyweight companies are on both sides, with the likes of Pioneer and Sony in the -R camp, and Philips and HP in the +R camp. Neither of these standards really mean very much however, because unlike completely incompatible formats (like the old Beta vs. VHS wars), both -R and +R are equally backward read compatible. And now that both are competing in the marketplace and both are doing rather well, it further diminishes the importance of the "standard".

Formats: -R/-RW comes in two flavors, DVD-R(G) for general use, and DVD-R(A) for authoring use. The general format is the one for consumers, and is available in all the consumer drives, while the authoring format is targeted at professional DVD production. There are two distinct differences between them:

1. General drives and media have a protection mechanism in them that prevents making bit-for-bit copies of CSS-protected DVD titles, such as Hollywood movies. Authoring media does not have this protection mechanism. This is now completely irrelevant since CSS is broken and the movies can be decrypted from the original DVDs.

2. Authoring media has a provision to allow it to be used as a replacement for DLT tape when you want to premaster a disc to be duplicated by a replication house. This is only useful if you're going to make DVDs for a replication house to run off hundreds of copies. It does NOT, however, support CSS encryption. So if you want to make a CSS protected premaster for a replication house to replicate, you can't use authoring media, and have to submit on DLT anyway. Not that CSS would protect your disc in the first place.

+R/+RW drives do not have this distinction, there is only one type, akin to the DVD-R(G) general use media.

Support/Useability/Firmware: The -R/-RW drives are made by a variety of companies, although Pioneer makes a large chunk of them. Due to the number of different manufacturers, there have been several drive firmware revisions, minor incompatibilities, and idiosyncracies between drives, media, & playability of the resulting discs in the -R world. These are getting resolved, but there have been hiccups and bumps in the road, and probably some more to come. On the other hand, virtually all of the +R/+RW drives are manufactured by Ricoh and relabeled with OEM labels. HP, Verbatim, etc. all get their mechanisms from Ricoh, and all use the same firmware. This has resulted in more consistent behavior, playability of the resulting discs, and fewer usability issues in the +R world. On the third hand because of +R/+RW's later arrival on the scene, it has taken some time for software manufacturers to add +R/+RW drive support to their products, but most of those issues are resolved now as well.

Technical Issues: The +R/+RW camp has made a big deal of their primary technical innovation, lossless linking. This is essentially extremely accurate positioning of the start of a written sector, enabling a +RW disc to be written to in a sector-accurate manner. This enables parts of a +RW disc to be rewritten without rewriting the other portions, and still maintains total DVD-Video playback compatibility, all without having to "finalize" the RW disc. -RW discs don't have lossless linking, but a different technology that they do have called DVD-Video VR essentially enables the same capability. In addition, both of these technologies are really only usable in a set-top DVD video recorder that uses RW discs, and very few of those exist (Philips makes one based on +RW, there may be others). The lossless linking and VR technology mean nothing on -R/+R discs, since it deals only with adding information to on replacing information on an already-written disc, which neither -R nor +R supports in DVD-Video format.

+RW discs also have a CAV write mode, which improves access time when used as a rewritable DVD-ROM. Microsoft has selected +RW to be supported natively in the next version of Windows for this reason. However, no drives currently support this write mode, so it's academic at this point.

All RW discs, + or -, must be formatted prior to use. However, +RW drives can format on-the-fly due to hardware in the drive that takes care of this. -RW discs must be manually formatted. This is why the write/rewrite speed of standard + drives is 2.4x/2.4x, as opposed to -RW's 2x/1x. The new 4x drives are 4x/2.4x for +, 4x/2x for -. The -R/-RW camp has answered this with software that background formats -RW discs, and quick-format options that let you start using the disc in just a few minutes.

Drive Cost: Virtually equal for both, with rebates and sales abounding in many outlets.

The Combo Drives: Sony has a drive, the DRU500A, that writes to both + and - media. NEC also has one, not generally available yet. The Sony drive has had some firmware difficulties, but that has been pretty much sorted out now. This might be useful if you are a production house and your customers have been requesting a specific format - you could write whatever they need with one drive. Otherwise, I personally believe the extra money for this drive is kind of a waste.


In short, I personally don't think you could go wrong with either format for home use. If you're going to make small production runs, the -R format may have a slight advantage due to media cost, but this is rapidly diminishing. In 6-12 months, the prices will be equal all the way around for the same manufacturer's media.

The reality is that each day that goes by with more drives of each type sold is that much less of a chance that either format will "win". In fact, I'd wager to say that enough of both types of drives have been sold now that you will not have to worry about supplies of one format of media disappearing or anything like that.

The other reality is that computer technology evolves. I guarantee you that far before either the + or - format becomes non-useable for whatever reason, you're going to want to buy the new Super-Whamidyne Blue-Ray High-Definintion SuperDVD recorder with all the new bells & whistles. Which no doubt will be available in 3 competing formats, complete with posturing atop soap boxes.

In short, just buy one and start making some movies, and have fun!


i hope this helps answer your question.