We are offering this advice as a guide only, these are not the absolute guidelines for storing your CD-ROM's. Please check with your governing agency as to your specific needs.
CD-ROM (Compact Disc Read-Only Memory) is the most popular and the least expensive type of optical disc. As the name indicates they come prerecorded with data which cannot be altered. It is an offshoot of the CD audio disc. The CD-ROM manufactured specification is an extension of the CD audio specification. The advantage of CD-ROM over other optical discs is that the introduced standard ensures that any CD-ROM drive will read any CD-ROM disc.
The most popular format of CD-ROM is the 74-minute or 650mb CD-R. These discs are advertised as holding 650MB, 680MB, or even 700MB of data. The reality is that they're all about the same size, and while you may get as much as an extra minute or two depending on the exact construction, you're not usually going to get an extra 30MB out of a disc labeled as 74-minute media.
It should also be noted that hard drive manufacturers don't measure megabytes in the same way that CD-R and RAM manufacturers do. The "MB" for CD-R's and RAM means 1024x1024, but for hard drives it means 1000x1000. Keep this in mind when purchasing a hard drive that needs to hold an entire CD. A data CD that can hold 650 "RAM" MB of data holds about 682 "disc" MB of data, which is why many CD-R's are mislabeled as having a 680MB capacity (the notion of "unformatted capacity" is a nonsensical myth.)
A CD-ROM has one track that spirals from the center to the outside edge. The track is divided into sectors of equal length and density. Files are stored on contiguous sectors. Fragmentation of files cannot happen because data can be written only once. However, there are CD-RW (CD-ReWritable) discs available (can be written to over and over like a cassette tape) Most CD writers can write to either disc format. FicheNet Imaging Solutions does not use any CD-RW's for job output unless specifically requested by the end-user.
CD-ROM drives are characterized by the spin rate. The spin rate is rotation speed of the disc and it influences the information retrieval speed (access time). Currently (early 2000) quad (4x) hex (6x) and octal-speed (8x) CD-ROM writers are available and read only drives are available up into the 52X and higher range!.
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