CompuServe Messages

Here's some analogies that might help you understand: 1) The term "Compact Disc" describes the physical media. Saying "Compact Disc" is like saying "3.5 inch floppy disc". 2) "CD-ROM", "Red Book", "CD-ROM XA" are all sector formats. They all use the same physical media ("Compact Disc") but the sectors are laid out differently. It's like 720K 3.5 inch floppy disks and 1.44M 3.5 inch floppy disks. Physically they are the same, but they have different sector formats. Some drives can use both sizes of disk, some only one or the other. Likewise, some Compact Disc players can only play digital audio Compact Discs (also called "CD-DA" or "Red Book", since the CD-DA specification has a red cover), some can read CD-DA and CD-ROM (CD-ROM is also called "Yellow Book", and still others can read CD-DA, CD-ROM, and CD-ROM XA. 3) ISO-9660 and High Sierra are volume formats. They determin where directories are placed on a disc and how they are formatted. This is similar to formatting a floppy disc. Both the Mac and the PC can use 720K 3.5 inch floppy disks. However they use different volume formats (Mac uses HFS, PCs use DOS). That's why the same physical floppy disk can be formatted on either computer, but once formatted it can only be used on that computer. ISO-9660 and High Sierra were designed to be portable volume formats. In order to read them on a Mac or PC, a special driver is loaded that translates between ISO-9660 and High Sierra and the computer's native disk format (HFS or DOS). A CD-ROM can use other volume formats besides ISO-9660 or High Sierra. Sometimes a CD-ROM is formatted using a computer's native format, such us HFS or SunOS. However, this means the disc can only be read by the computer that uses that native format. 4) There are no CD-ROM standards for data or program file formats. A program on a CD-ROM can only be executed by the operating system that the program was written for. 5) CD-ROM drives are not inherently computer specific, although their interfaces may be. For example, some drives require controllers that are only available as PC expansion cards. Others There is 1 Reply.