====== CD/DVD types and names ======

There are many different types of CDs and DVDs so that you can easily get confused. We'll try to explain the most common ones for a better understanding. There are many more formats though, you can look them up at [[http://wikipedia.org/|Wikipedia]] if you like.

At this point, you might also want to [[http://www.digitalfaq.com/reviews/dvd-media.htm|check which manufacturer produces the highest quality media]].

^ Disc type ^ Description |
^ CD / CD-ROM                     | **C**ompact **D**isc (or **CD** **R**ead **O**nly **M**emory), very commonly used term. Usually this refers to non-writable discs. |
^ CD-R       | //Writable// discs (or **CD R**ecordable). This means that you can only burn data a single time on it, or multiple times when using //multisession mode// until the capacity is exhausted. You cannot physically delete data (unless you damage the disc and the like). |
^ CD-R 74/80/... | The numbers behind CD-R indicate the capacity of the disc. 74 for examplease means 74 //minutes// of (uncompressed) music (= 640MB). Below this table is a list of all capacities. |
^ CD-RW    | //Rewritable// discs (**CD R**e**w**ritable). You can not only add data, but you can also erase the whole data on disc in oder to put different contents on it. Usually you can erase it a few hundred times. If you want to use this type of disc like a floppy disc, you have to use programs like [[http://fileforum.betanews.com/detail/Nero_InCD/1013387700/1|Nero InCD]]. |
^ DVD / DVD-ROM | **D**igital **V**ersatile **D**isc (or **DVD** **R**ead **O**nly **M**emory). Basically the same as CD-ROM, however, a DVD typically has a 6 times greater capacity than a CD.|
^ DVD-R / DVD+R      | //Writable// DVDs (or **DVD R**ecordable). Basically the same as CD-R with greater capacity. Note that DVD-R (say: DVD minus R) and DVD+R (say: DVD plus R) is a different kind of disc. There is virtually no difference between those types, but it might be the case that your DVD burning device can only burn DVD-R or only burn DVD+R. Most modern devices support both formats equally though. |
^ M-Disc DVD+R      | //Writable// DVD+R discs with special properties. By using an inorganic data layer, these discs can preserve data for up to 1000 years ([[http://millenniata.com/technology/|according to the manufacturer]]). Since usual lasers cannot burn these discs, a drive that supports M-Discs is required. |
^ DVD-RW / DVD+RW | //Rewritable// DVDs (**DVD R**e**w**ritable). Basically the same as CD-RW with greater capacity. Note the difference between + and -, see DVD-R/DVD+R above. |
^ DVD-RAM | Stands for DVD **R**andom **A**ccess **M**emory. It is comparable to a DVD+-RW. However, it has a much higher lifetime (approx. 30 years) and can be erased much more often than a DVD+-RW (at least 10.000 instead of 1.000 times). Also, it has higher data security than a usual DVD. Additional to that you can use it like a floppy disc, if you have [[http://www.megaupload.com/de/?d=MKRS8AHW|appropriate drivers]]. |
^ DVD ... DL | Stands for **D**ouble (or **D**ual) **L**ayer. Double layer discs have twice as much disc space than usual DVDs. |
^ HD-DVD | Stands for **H**igh-**D**efinition **D**igital **V**ersatile **D**isc. HD-DVDs are comparable to DVDs with higher capacity, but have already been abandoned by their creators. |
^ BD-R | Stands for **B**lu-Ray **D**isc **R**ecordable. Basically comparable to a DVD+-R, but has a much higher capacity.|
^ BD-RE | Stands for **B**lu-Ray **D**isc **Re**writable. Basically comparable to a DVD+-RW, but has a much higher capacity.|

====== Disc capacity ======

^ Disc name ^ Capacity |
^ CD ... 74 | 74 minutes of uncompressed audio or ≈650.3 MiB of data (681984000 bytes). |
^ CD ... 80 | 80 minutes of uncompressed audio or ≈703.1 MiB of data (737280000 bytes). |
^ CD ... 90 | 90 minutes of uncompressed audio or ≈791.0 MiB of data (829440000 bytes). **Disc size cannot be detected automatically and disc needs to be burned using the "Overburn" option.** |
^ CD ... 99 | 99 minutes of uncompressed audio or ≈870.1 MiB of data (912384000 bytes). **Disc size cannot be detected automatically and disc needs to be burned using the "Overburn" option.** |
^ DVD-R (DVD-5) | 4.7 GB ≈ 4.38 GiB ((in Windows, if you see GB or MB it usually refers to GiB and MiB respectively)) of data (4707319808 bytes). CDBurnerXP assumes a size of 4706074624 bytes for disc spanning (lower disc sizes have shown in practice). |
^ DVD+R (DVD-5) | 4.7 GB ≈ 4.38 GiB ((in Windows, if you see GB or MB it usually refers to GiB and MiB respectively)) of data (4700372992 bytes). |
^ DVD ... DL (DVD-9) | 8.5 GB ≈ 7.95 GiB of data (8543666176 bytes). |
^ HD-DVD Single Layer | 15 GB ≈ 14.0 GiB of data (15076554752 bytes). |
^ HD-DVD Dual Layer | 30 GB ≈ 31.1 GiB of data (33393473536 bytes). |
^ BD Single Layer | 25 GB ≈ 23.3 GiB of data (25025314816 bytes). |
^ BD Dual Layer | 50 GB ≈ 46.6 GiB of data (50050629632 bytes). |
^ BD XL 100 GB | 100 GB ≈ 93.2 GiB of data (100103356416 bytes). |
^ BD XL 128 GB | 128 GB ≈ 119.2 GiB of data (128001769472 bytes). |

If you are not familiar with the meaning of GB, GiB, MB etc, [[http://en.wikipedia.org/wiki/Byte|read a wikipedia article on that matter]]. Basically vendors specify capacities (of hard drives for example) using GB/MB which results in a higher value compared to GiB/MiB. However, Windows will usually only tell you the GiB/MiB value, despite the fact that it writes GB/MB as unit behind the value.

====== Device compatibility ======

How do you know whether or not your drive can burn a particular type of disc?

The most accurate information will probably be in the manual of your drive. However, most drives also have a few icons at the front which help to identify its abilities.

^ Icon ^ Description |
^ {{images:180px-cdlogo.svg.png?128|}} | If you have this icon on your drive, it usually can only //read// (and not write) CDs.  |
^ {{images:180px-cdrlogo.svg.png?128|}} | If you have  this icon on your drive, it usually can //read// and //write// CD(-R)s, but cannot write CD-RW discs. |
^{{images:180px-cdrwlogo.svg.png?128|}} | If you have this icon on your drive, it usually can //read// and //write// CD-Rs and CD-RWs. |
^ {{images:200px-dvd.svg.png?128|}} | This icon hints at DVD capabilities (at least, reading). If it can also write DVDs, "DVD-R" or "DVD-RW" is usually written below. Without this icon, your drive can neither read nor write DVDs. |

Note that there might be modified icons like for "CD-RW Highspeed" which allows writing suitable CD-RWs with higher speed or DL which refers to Double Layer DVDs.

====== Usage of disc types ======

Maybe you find it hard to decide which type of disc to use for each purpose. Here is our recommendation.

^ Task ^ Disc type |
| Audio-CD for music player etc. | CD-R with 80 minutes is the default choice. Rewritable discs will not work in every audio player. |
| Short term data storage, just for "transport" | CD-RW for small and DVD+-RW for large amount of data. This allows you to use the disc multiple times. |
| Backups, long term data storage | DVD-RAM. They have a quite high lifetime and data security. Or even better yet, if you can afford it: [[http://millenniata.com/m-disc/|M-Discs]] |
| Movies | Usually DVD+-R, unless you want to use the same disc multiple times. A movie won't fit on CD. There is such a thing as an SVCD (method to burn movies to CD), but this results in a rather low-quality movie and multiple discs are required. |
| Photos | Those will usually fit on a CD-R or CD-RW (use the latter one if you intend to reuse the disc for other purposes later). |