heres a whole bunch of info on the different types of cds and dvds

first of all, heres what the basic types of cds/dvds are

regular cd size is 700MB (Mega-Bytes), 74min/80min/99min

dont trust the 99min cd's because your sacrificing either quality, or writing really close the the edge which sacrifices compatability with many devices

dvd size is 4.7GB (Giga-Bytes) or 8.5GB if it is dual(also known as double) density

there are also Blu-Ray disks that hold 54GB and HD-DVD disks that hold 30GB

the + or - symbol(ie: CD-R or CD+R) comes from the fact that 2 different companies came out with basically the same thing and gave it a different name. they are not compatible though most drives support both.

here are the meanings of the symbols you'll see on a CD/DVD drive:

This drive can read all types of CDs: CD-ROM's, CD-RW's, CD-R's, and audio CDs. it can't record

This drive can do all that the previous one can as well as record on CD-R discs and CD-RW discs. it has Standard-Speed, High-Speed, or Ultra-Speed recordong capabilities respectively.

this symbol means either,depending on the circumstances, that this drive can read DVD-ROM discs or if it is RAM-Read, it can read DVD-ROM discs, as well as type II DVD-RAM dics and DVD-R discs.

this drive can read DVD-ROM discs, DVD-R discs, type II DVD-RAM discs, and DVD-RW disks.

this drive can read type I and type II DVD-RAM discs, DVD-ROM discs AND can record on type I and type II DVD-RAM discs.

this drive can read DVD-ROM, DVD-R, DVD-RAM, and DVD-RW discs AND can write to DVD-R and type I & II DVD-RAM discs.

This drive can read DVD-ROM discs, DVD-R discs, DVD-RAM discs, and DVD-RW discs AND write to DVD-R discs,and type I & II DVD-RAM discs.

here is the same basic data in a table