CD-ROM and DVD-ROM Drives

It's an absolute necessity that your computer system be capable of reading CDs since the vast majority of current software is distributed exclusively via CD-ROM. it's likely that the easiest way, and perhaps the only way, to install your operating system is via CD so you'll want to have a working CD reader from day one. You have two major options in this case: A CD drive or a DVD drive.

What is a CD-ROM?

CD-ROM stands for "Compact Disc Read Only Memory"; a computer CD is physically the same as an audio CD; only the way in which the data is formatted is different. A CD-ROM can hold about 650 MB of data, which is thousands of times greater than the storage capacity of a 3.5 inch floppy disc but even the fastest CD-ROM drives have much slower access speeds than hard drives. The main disadvantage of a CD-ROM aside from its relatively slow access speed is that you cannot write to one, meaning you can't change the data that's on a CD-ROM unless you have a write-capable drive and are using writeable CDs (generally called CD-RW); we'll talk about writeable drives in another article. The reason CD-ROMs are so popular with software distributors is a combination of their storage capacity and their low manufacturing cost.

Despite the usefulness of the CD-ROM drive, the technology is now outdated by the DVD-ROM. There is still a great deal of software distributed on CD-ROM, but since a DVD-ROM drive is capable of reading CD-ROM discs, there's no real reason to buy a CD-ROM drive anymore. If, for some reason, you decide not to get a DVD-ROM drive you will definitely need a CD-ROM drive. Before you decide to buy, pay attention to the CD-ROM drive's access speed. This is generally advertised at for example 45x or 32x; the higher the number, the faster you will read data from the CD.

What is a DVD-ROM?

DVD-ROM is a technology very similar to CD-ROM, but the storage capacity (4.7 GB) is about seven times greater than that of the CD-ROM (650 MB). In addition, the DVD-ROM drive can be used to watch movies displayed either to a computer monitor or optionally to a TV if your video card offers a TV-out feature. One important note is that the speed factor for DVD drives refers to a rate of transfer about nine times higher than that of the CD-ROM drive; thus a 1x DVD-ROM drive will read at the same speed as a 9x CD-ROM drive. As mentioned above, DVD-ROM drives are fully capable of reading both CD-ROM data and audio CDs; since they are relatively inexpensive, you might as well get a DVD-ROM drive and skip the CD-ROM drive altogether. As for the speed, 16x drives are not exorbitantly priced so you might as well aim for that; 12x is acceptable but don't go too much lower.

In summary, although you certainly want your computer to be able to read CDs, you don't need a CD-ROM drive unless you don't have a DVD drive, which you might as well have since it's better technology, compatible with CD technology, at an acceptable cost. If you do get a CD drive, what you probably want is a write-capable drive, which we will discuss in the next article.