CD - DVD FAQs

A CD-R is a recordable CD that can only be recorded once. They cost about $1 at Socorro Office Supply (SOS). A CD-R can be read in most CD readers, including old PCs.

A CD-RW (recordable/writable) disc can be recorded once like a CD-R or written to multiple times (~1000). If using it in the multiple write mode, you format it first like a floppy disk (takes about 15 minutes with a 4x writer) and then you can write to it like any other removable disk. The rewritable CDs can only be read on more modern PCs or older ones with special software. They cost about $2 at SOS.

CD-Rs (and CD-RWs used in the CD-R mode) will hold 650 MB. CD-RWs after formatting for use in the rewritable mode hold 530 MB.

CNET has a good article explaining this in more detail.

Q. When looking at specifications for CD-RW or DVDxxx drives, what do the 3 numbers mean?
A. The 3 numbers, eg. 8/4/32, translate to write/rewrite/read speeds. If you forget the order, just remember that in most cases the biggest number (fastest speed) is the read speed, the next highest number the write-once speed, and the smallest number (slowest speed) is the rewrite speed. This pertains to DVD writers too.

The numbers are based on the read speed of the original drive made for that type of device. For CDs, the original CD-ROM (the 1x version) could read data at a speed of 150 KB/sec. The original DVD-ROM read data at 1.4 MB/sec, about 10 times faster than a CD-ROM. So to compare CD and DVD data-transfer speeds, multiply the DVD's "x" number by 10 to get a rough equivalent to the CD "x" number. For example, a 2.4x DVD reads data at roughly the same speed as a 24x CD.

Q. What brand name of CD-R and CD-RWs should I buy?
A. I've had good results with Verbatim, the brand Socorro Office Supply stocks. Don't buy generic unless you're willing to accept some bad ones. Make sure you buy media that support the speed of the drive you will be using to record/write the discs to cut down on errors. Click here for a detailed CNET review on CD-R media.

Q. Is it safe to write on CD-R and CD-RW?
A. I haven't had any problems using Sharpie markers, but I write lightly and don't dig in. Click here for an article by Roxio.

Q. Should I use CDs or DVDs for storage?
A. CDs hold a lot less data (530 MB and 650 MB) than DVDs. But CD-Rs and CD-RWs are a lot cheaper, and more PCs have CD drives than DVD drives. DVDs hold lots more data--4.7 GB single-sided and 9.4 GB double-sided. But the DVD media is pricey, and DVD readers are not as common as CDs.

Q. What are all those DVD formats?
A. DVD+RW, DVD-RW, DVD-RAM, DVD-ROM...what, you wanted an explanation? OK, try here.