This article is based on an interaction that took place in the Ask a Techo forum on 30 June 2004

The question: ....  To me, terms like "DVD+RW/+R with CD-RW Combo Drive” are a foreign language while the plethora of DVD and CD player/writer formats available sends me into a spin. What does it all mean? Is it important?

The answer:...

In the beginning… there was CD-ROM - it stands for Compact Disk - Read Only Memory. What some bright spark did was use CD audio technology and used it to store data. CD-ROM has been around for quite a while now. Holds about 700 MB of Data

CD-R stands for CD-Recordable. This is where they developed the function of being able to write to a CD-ROM. Its good, but you can only write to the disk once (mostly)

CD-RW stands for CD-ReWriteable. This format is similar to CD-R but you can reformat (erase) the disk and write to it again!

CD-R Multisession - this is where they have managed to allow you to write multiple burn sessions onto the same CDR disk. This means you can copy some data to the disk, then add a bit, then add a bit, until the disk is full. It works, but watch out for compatibility issues across different PC's.

As a means of storing and moving data, CD's are declining in popularity in favour of USB flash drives.

DVD-ROM - this is where they used the technology of DVD disks to store data. DVD's can hold either 4.7 gig or 9 gig of data.

DVD-R and DVD+R are recordable versions of DVD-ROM. Both formats are very similar. Essentially, one format is a consortium that have paid a royalty to the holders of the DVD patent, the other is a consortium that have not!

Expensive DVD players may not play one of the formats. Cheap DVD players (especially those made in China) don’t care and play anything!

DVD-RW and DVD+RW are the same thing as above but are Rewriteable.

Sony have released a new DVD recorder that can now (as at 30 June 2004) do 9 Gig (double layer) disks. Previously DVD+r-r could only do 4.7 gig disks.

Cost of blank disks: CDR - $0.90, DVD-r+r - $2.50