CD-ROM, DVD-ROM reader and writer units

CD-ROM, CD-RW, DVD-ROM, DVD-RW to read write on CDs.

Every Computer comes with a CD-ROM or DVD-ROM unit now. There is also CD-RW and DVD-RW units that are writers to make your own data CD's or DVD's on a blank media. You can use the writers to make backup copies of your original data CD's or DVD movies or can use them to simply store your files for backup.

CD-ROMs are now obsolete and are replaced by DVD-ROMs that are sold at a very cheap price. DVDs can hold much more data than the 650-700 MB of data that a CD-ROM can have. When CD-ROMs first came out, they were connected to a special ISA controller card or sound card. Now CD units are connected on the standard IDE ports of your computer.

DVD-ROMs will read standard 650-700 MB data CDs, audio CDs and DVD movies. Since DVD-ROM units read all actual CD/DVD media and their prices went down a lot, they replaced the old CD-ROM as a standard component of a computer.

CD-RW can write data to a 650-700 MB blank CD. Some are also able to re-write on rewritable CD. Rewritable CDs are fun since they can be erased and re-written to up to 1000 times. The write once CDs cannot be erased and re-written to, you can only add data to them until they are full.

Picture of a cd-rom unit

A DVD-RW is like the CD-RW and can write data to a blank DVD media. It will hold much more data than a standard CD and some can also do double-layer writing. Double-layer writing is to write data to two different depth of the media to store more data on the same DVD. Movies are usually written on multi layers and have to be compressed to be written on a single layer media.

Installing a CD or DVD unit to a computer is easy. It's connected on an IDE port alone or with an other IDE device like an other CD unit or a hard disk. You can set the CD unit to slave and connect it with an other device set as master on the same 40 pin cable or be installed alone as master or slave on one IDE port. If the system use ATA-66 or ATA-100 IDE hard disk, the CD unit can be set to use CS (Cable Select) and installed on the same 80 pin cable with the hard-disk.

CD and DVD-ROMs have an audio connector that plugs on the sound card to send the analog sound signals to the sound device. This is to play audio CDs for example, but most computers will not need this cable anymore since the audio tracks will be dealt straight by the sound card.