CD : Computer Hardware Buyers’ Glossary

CDROM (Compact Disc Read Only Memory) or sometimes CD-ROM (Compact Disc — Read Only Memory). Computer programs come written on discs that look just like ordinary audio CDs. They can hold about 600 MB of data, or the equivalent of 400 floppy diskettes. A computer CD-ROM drive is much like one in a home stereo, except that it spins 2×, 4×, 8×, 12×, 16× or even 48× as fast. The speeds are exaggerated. They only apply to the outermost track and in burst mode. In practice drives won’t be anywhere near as fast as advertised. The faster it spins, the faster data can be read. With the appropriate cable, you can even play audio CDs (Compact Disks) on a computer CD-ROM drive. Digital CDs can be read, but not written on. This means there is no practical way to brand them with your name, or even with a serial number. Often a magic password comes with a CD (Compact Disk), on a piece of paper you are bound to lose. Without the password, you can’t install (or re-install) the software. Use a red Sharpie fine tip permanent marker to write the password/serial number/key on the top side of the CD where you can’t lose it. Don’t apply any sort of sticky label since it may come off inside the drive, unless it is specially designed for CDs. The two most common kinds of CD-ROM are SATA (Serial ATA), EIDE (Extended Integrated Drive Electronics) and SCSI (Small Computer System Interface). Unfortunately there are also several other proprietary types that cause nothing but trouble often bundled with sound cards.

You would think CDs would play from the outside in, like vinyl LPs (Long Play recordings) but they start at the centre and work out. This seems odd given the outer tracks are longer than the inner. The advantage of this is it often leaves the outer tracks unused which are often smeared with fingerprints by people failing to pick up the CDs properly.

If you are labelling a set of CDs, particularly a set of audio CDs, label them so you can read the disc number no matter how the CD is oriented, like the CD on the left.