CDs are now the main medium for distribution of software. If you go to the computer shop to buy a program, you'll have to look a lot harder to get that program in a diskette format. In some cases, you'll have to special order it. Why? Simple. A diskette can hold only 1.44 MB of data. Therefore, a software company would have to use several diskettes to hold a large program. Even with compression technology, this can amount to 15 or more disks. On the other hand, a single CD can hold about 650 MB of data and it costs less then a dollar to make. .
CDs are coated with aluminum to reflect light and imprinted with a series of pits and flat areas. Reading these pits or flats denote 0's or 1's, the building blocks of binary language which the computer uses. A thin laser beam reads the pits or the flats while the disk is spinning. Light reflects from the flat surfaces, not the pits. So a photo detector reads what is reflected and sends the 0's and 1's to the CPU. This is simply binary code, and is how the CPU interprets data. .
CD-ROM drives come in many styles. They are both external and internal. They also come in different speeds. The speed is denoted in terms of how much faster it is than a standard audio CD player. Therefore a 2X drive is twice the speed of your stereo's CD player, and so on. Technology has advanced quite a bit. Today, 24X, 32X all the way up to near 50X is quite common. Another choice is what interface you want. CD-ROM drives come in IDE, SCSI, or other proprietary interfaces, such as that of Creative's original multimedia kit. Most drives are IDE, and that is the easiest type to install. .
CD-ROM drives are included in just about every PC on the market today. They are pretty simple at the end-user level, but there is a lot more to know about CD-ROM drives than most users care to know. This article will cover some of these things, including how they work, the different types, etc. .
CD-ROM Media .
