Optical Storage Devices Background:
Capacity:
CD-ROM 650MB
DVD 4.37GB [8.5GB for Dual Layer (DL)]
Blu-ray 25GB [Dual Layer 50GB]

CD's:
  Used primairly for music also for data backup.
DVD's:
  Used primairly for video/movies, software and videeo game distribution and data backup.
Blu-ray (BD)
  Blu-ray won out over HD DVD for high-definition (HD) video and data storage.

At manifest-tech.com/media_dvd/dvd_compatibility.htm they ask:
What is going on with DVDs? The industry states that discs should last 50 to 100 years, but on-line reports claim significant problems with both pressed and recordable discs. Can movie discs wear out and fail from "DVD rot?" Is recordable DVD a trustworthy archival media, or is there evidence that discs can wear out from extended play? And what is the situation with the compatibility of recordable media? Is there a way to guarantee reasonable compatibility, some magic combination of formats and brands, software and burners, content and players?

There are two ways of producing optical media:
Pressing - 'pits and lands' which creates pits in the reflective area.
Burning - A laser causes spots of organic dye to go opaque and obscure the reflective surface.

Unlike pressed CDs/DVDs, 'burnt' CDs/DVDs can eventually 'fade', due to five things that effect the quality of CD media: Sealing method, reflective layer, organic dye makeup, where it was manufactured, and your storage practices.
See DVD cross section below.

The silver and aluminum alloys used in virtually all blank CD/DVD media require a lacquer protective seal to avoid oxidation. The protective seal on cheaper disks can deteriorate.
Some (very expensive, $2/disk) media uses gold instead which doesn't oxidize.

The original organic (Cyanine) dyes would break down in about 10 years.
Taiyo Yuden, Mitsubishi Chemicals, Mitsui Co., Ciba and TDK now produce dyes that are supposedly stable for 70 years.
Taiyo Yuden's 'Super Cyanine' and TDK's 'metal-stabilized Cyanine' dye are claimed to last 70 years and Mitsubishi (Verbatim) claims their Metal Azo dye is stable for 100 years, although the shelf life of the media typically doesn't exceed that of TDK or TU.
See Problems - Maintenance below for more information.

Source: Most of the above was from How To Choose CD/DVD Archival Media, by Patrick McFarland at Ad Terras Per Aspera

Types:
DVD-R (dash format) is a write-once format that came out first. It is compatible with 93% of all DVD Players and most DVD-ROMs (Compuer DVD drives). Early Macs (e.g. PowerBooks) only supported DVD-R
DVD+R (plus format) is a newer write-once format compatible with about 89% of all DVD Players and most DVD-ROMs. It has some advantages over DVD-R (see below)
DVD-RW is a rewritable format similar to DVD-R compatible with about 70-79% of DVD Players and most DVD-ROMs.
DVD+RW is a rewritable format similar to DVD+R compatible with about 70-79% of DVD Players and most DVD-ROMs.
DVD-RAM has the best recording features but it is not compatible with most DVD-ROM drives and DVD-Video players. Think more of it as a removable hard disk.
DVD.. DL are dual layered discs thaat can hold 7.95GB.
Most drives now support DVD-R, DVD+R and DVD-RW
According to How To Choose CD/DVD Archival Media DVD+R is better than DVD-R for data preservation, because of superior error correction, 'wobble' tracking, and data writing methods.

CD-RW, DVD-RW, or DVD+RW media are NOT recommended for permanent storage.

Speed:
DVD:
1x (CLV †) 1350 kB/s write speed = 58 minutes
2x (CLV) = about 29 minutes
2.4x (CLV) = about 24 minutes
4x (CLV) = about 14.5 minutes
6x (CLV/ZCLV) = about 10-12 minutes
8x (PCAV/ZCLV) = about 8-10 minutes
12x (PCAV/ZCLV) = about 6.5-7.5 minutes
16x (CAV/ZCLV) = about 6-7 minutes

† See terms below for CLV ...

Manufacturers:

At www.best-dvd-burning-software-reviews.com/best-blank-dvd-media.asp they say:
Most blank DVD media is produced by a relative small number of factories, located in several different places. These factories are present in Taiwan, Japan, Singapore, Mexico, Hong Kong, India, and Ireland... maybe a few more, but not many. The best media generally comes from Japan and Singapore. The worst typically comes from Taiwan * (in stores) and Hong Kong (online).
Companies like Memorex, Fuji and Imation all outsource to media vendors.
* Some high quality Verbatim disks are made in Taiwan.

They recommend:

• 95-100% reliable results: Mitsubishi (Verbatim *), Taiyo Yuden, Maxell, TDK..
    You can't buy Taiyo Yuden (considered the best) directly in the US,   but Verbatim and TDK carry their media.   SuperMediaStore.com has them.
  * Verbatim has been relabeling other brands of disc as their own. If the box/spindle/cakebox the discs come in doesn't have the icon (meaning they are manufactured with Verbatim's proprietary Azo dye), then don't use them.
  Verbatim DVD-R made in Taiwan (UPC/EAN code is 023942951018) at Best Buy got a good review at VideoHelp.com.

• 80-95% success rate: Sony, Fuji
  
• < 80%: Mainly no-name brands
  
• Manufacturers who re-brand media from other manufacturers, Memorex (CMC, Ritek, Moser Baer, Mitsubishi, Prodisc, Ricoh, Infodisc, Moser Baer), HP (CMC, Ricoh, Mitsubishi, Fujifilm), Dynex (Ricoh) and Store Brands, e.g. Staples (CMC) were not rated. [Codes in () are Media ID's for the actual manufactures of the media.]

• 1st Class (Excellent): MCC - Mitsubishi/Verbatim; TY or YU - Taiyo Yuden; SONY 04, 08 some 16; TDK (TDK, TTG†), MAX, MXL - Hitachi Maxell
  
• 2nd Class (OKay): Ricoh, CMC, Prodisk, Fuji, Philips, some Sony (made n Japan and Taiwan)...
  
• 3rd Clas (No good): Samsung/BeAll (BEALL), InfoMedia (INFOMER), Sony (SONY16D1 made in Malaysia)
• Not rated: Memorex, Fuji and Imation all outsource to media vendors.

Infosmart makes fakes with the TYG02 and MCC02 codes. They are no good.

At club.cdfreaks.com/f33/dvd-r-media-best-long-term-storage-2006-2007-a-183683/ they recommend:
Mitsubishi / Verbatim, Taiyo Yuden

and say:
Sometimes the same MID (Manufacturer ID) and quality disc can exist in various incarnations. Take Maxell for instance. MXLRG03 exists in Consumer Grade, Pro or Plus Grade (depending on your region), and then here in North America, we have BQ grade, which is a MXRG03 with a hardend coating for extra protection. I would vote for the BQ Maxell, but not the consumer grade Maxell.

Some disks have a serial numbr engraved in the outer hub ring.

Drives: Samsung SH-S223F (SATA), Samsung SH-S202J (IDE) and Pioneer DVR-216D (SATA) are recommended at cdfreaks.com

Review of Iomega Super DVD Writer 16X16 with comparioson of other writers at cnet.

Maintenance - Storage - Problems:
There are several ways DVD's can fail:

• DVD Rot - The organic dyes which turn opaque when hit by the laser in recording can oxidize and break down. Newer dyes last longer. See above.
  -Symptoms of the rot include picture break-up and freezinng at a specific place on the disk. The main cause is believed to be poorly designed cases.
  
• Delamination where the layers separate.
  Delamination shows up as a coffee-like stain that prevents the disc from playing.
• Scratches
• Warping

    * 75 yrs at 50°F, 25%RH
    * 45 yrs at 59°F, 30%RH
    * 20 yrs at 68°F, 40%RH
    * 10 yrs at 77°F, 25%RH

Notes:
Mac 1GHz PowerBook G4 Superdrive only burns DVD-R at 1x (there is a firmware upgrade that allows burning at 2x)

Links:
Audio/video
How To Choose CD/DVD Archival Media, by Patrick McFarland at Ad Terras Per Aspera
club.CDFreaks.com
DVD Association (DVDA)
Optical Storage Technology Association (OSTA, www.osta.org)
DVD Rot at manifest-tech.com
Can I play my recorded DVDs in other DVD players - What are the DVD Formats?
cdr-zone.com
http://www.dvdforum.com/
NIST Digital Preservation Program www.itl.nist.gov/div895/isis/datastorage.html
DVD Compatibility Test Ralph LaBarge, AlphaDVD DV Magazine, July 2002 www.dvdtoday.com/Recordable_DVD_Test.htm
Care and Handling Guide for the Preservation of CDs and DVDs National Institute of Standards and Technology (NIST) CLIR and NIST joint project NIST Special Publication 500-252, May 2003 PDF - 52 pages (1.55 MB file) www.itl.nist.gov/div895/carefordisc
Care for CD & DVD Media at Iowa State
Care and Handling of Alternative Media at the Margaret B. Harrison Preservation Department at UC Davis
digitalfaq.com/media/dvdmedia.htm
dvdforum.com
The Basics of CD's and DVD's
Introduction to CD and DVD. at CDT
www.best-dvd-burning-software-reviews.com/best-blank-dvd-media.asp
club.cdfreaks.com/f33/dvd-r-media-best-long-term-storage-2006-2007-a-183683/

Terms:
CAV = Constant Angular Velocity, the DVD is written at a constantly increasing speed.
The CLV mode sets the disc's rotation at roughly 1400 RPM decreasing to 580 RPM (1x CLV) as the optical head of the player or recorder reads or writes from the inner to outer diameter (ID to OD).
CD = Compact disk
CLV = Constant Linear Velocity, the DVD is written at a constant speed.
DVD - Digital Versatile/Video Disk (see types above)
PCAV = Partial Constant Angular Velocity, the DVD is being written at an increasing speed until a certain speed. After this speed it will not increase anymore.
PCI = Peripheral Component Interconnect - The most common I/O bus internal to computers.
SLI = NVIDIA SLI™ (Scalable Link Interface) takes advantage of the increased bandwidth of the PCI Express bus architecture
ZCLV = Zone Constant Linear Velocity, the DVD is divided into zones. After each zone the write speed is increased.
See: DVD Glossary